Form N-CSRS FRONTIER FUNDS, INC. For: Dec 31

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM N-CSR

CERTIFIED SHAREHOLDER REPORT OF REGISTERED
MANAGEMENT INVESTMENT COMPANIES

Item 1. Reports to Stockholders.

SEMI-ANNUAL REPORT

Frontier MFG Global Equity Fund

Frontier MFG Global Plus Fund

Frontier MFG Core Infrastructure Fund

Frontier MFG Select Infrastructure Fund

Frontier Timpani Small Cap Growth Fund

Frontier Phocas Small Cap Value Fund

Frontegra Asset Management, Inc.

December 31, 2018

Beginning in February 2021 for the Funds, as permitted by regulations adopted by the Securities and Exchange Commission, paper copies of the Funds' shareholder reports like this one will no longer be sent by mail, unless you specifically request paper copies of the reports from the Funds or from your financial intermediary, such as a broker-dealer or bank. Instead, the reports will be made available on a website, and you will be notified by mail each time a report is posted and provided with a website link to access the report.

If you already elected to receive shareholder reports electronically, you will not be affected by this change and you need not take any action. If you invest through a financial intermediary, you may elect to receive shareholder reports and other communications electronically from the Funds by contacting your financial intermediary (such as a broker-dealer or bank). If you invest directly with the Funds, you will receive shareholder reports electronically beginning in February 2021.

You may elect to receive all future shareholder reports in paper free of charge. You can request to continue receiving paper copies of your shareholder reports by contacting your financial intermediary or, if you invest directly with a Fund, calling 1-888-825-2100 to let the Fund know of your request. Your election to receive shareholder reports in paper will apply to all funds held with Frontier Funds, Inc.

TABLE OF CONTENTS

This report is submitted for the general information of the shareholders of the above-listed Funds. It is not authorized for distribution to prospective investors unless accompanied or preceded by an effective Prospectus for the applicable Fund. The Prospectuses may be obtained by calling 1-888-825-2100. Each Prospectus includes more complete information about management fees and expenses, investment objectives, risks and operating policies of the applicable Fund. Please read the applicable Prospectus carefully.

Frontier Funds, Inc. are distributed by Frontegra Strategies, LLC, 400 Skokie Blvd., Suite 500, Northbrook, IL 60062. Frontegra Strategies, LLC, member of FINRA and SIPC, is an affiliate of Frontegra Asset Management, Inc. and Timpani Capital Management LLC, the Funds' investment advisers.

DEAR FELLOW SHAREHOLDERS:

We are pleased to report on the progress of the Frontier Funds over the past six months ending December 31, 2018. The S&P 500 Index was down 6.85% and small capitalization stocks were down, with the Russell 2000^® Index returning -17.35%. International stocks, as measured by the MSCI EAFE Index, returned -11.35% over the six-month period.

Fund Results

For the six months ended December 31, 2018, the Frontier MFG Global Equity Fund, managed by MFG Asset Management ("MFG"), returned -2.85% (net), while the Frontier MFG Global Plus Fund, Institutional Class, also managed by MFG, returned -2.71% (net). The Funds' benchmark, the MSCI World Index (Net), returned -9.10% over the same time period. The Global Plus Fund's Service Class shares returned -2.84% (net).

The Frontier MFG Core Infrastructure Fund, Institutional Class, managed by MFG, returned -3.12% (net) versus the S&P Global Infrastructure Index return of -6.64%, for the six-month period ending December 31, 2018. The Service Class shares returned -3.16% (net) over the same time period.

For the period from July 2, 2018, (inception), through December 31, 2018, the Frontier MFG Select Infrastructure Fund, also managed by MFG, returned -4.25% (net) compared to the S&P Global Infrastructure Index return of -6.30%.

The Frontier Timpani Small Cap Growth Fund, Institutional Class, managed by Timpani Capital Management, returned -15.62% (net) versus the Russell 2000^® Growth Index return of -17.33% for the six-month period ending December 31, 2018. The Class Y shares returned -15.74% (net) and the Service Class shares returned -15.63% (net) over the same time period.

The Frontier Phocas Small Cap Value Fund, managed by Phocas Financial, returned -20.39% (net) versus the Russell 2000 Value Index return of -17.36% for the six-month period ending December 31, 2018. The Service Class shares returned -20.35% (net) over the same time period.

Outlook

In late 2018, stock markets dropped dramatically amid rising concerns over the U.S.-China trade war and moderating global growth. Computerized trading strategies only exacerbated the selloff. This latest rise in volatility capped off an extraordinary year in global equities. The year started with optimism over "synchronized" global growth, which subsequently disappeared in the spring as the U.S. economy — fueled by tax cuts and fiscal stimulus — performed well while the rest of the world struggled. Equity volatility remained relatively low until early October, when it roared back due to the anticipation of U.S. monetary tightening and higher U.S. interest rates, along with fears that a trade war and overseas slowdown would eventually take its toll on U.S. growth and corporate earnings.

We live in uncertain times. Therefore, we will continue to oversee the investment management of the Frontier Funds with the skill and agility that have served our shareholders well in the past. As always, we appreciate your investment and continued confidence in the Frontier Funds.

Best regards,

William D. Forsyth, CFA

President

Frontier Funds, Inc.

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FRONTIER
MFG GLOBAL EQUITY FUND
AND
FRONTIER
MFG GLOBAL PLUS FUND

REPORT FROM MFG ASSET MANAGEMENT

Dear Fellow Shareholders:

The investment objective of the Frontier MFG Global Equity Fund and the Frontier MFG Global Plus Fund is capital appreciation. The objective is measured against the MSCI World Index (Net).

Performance Review

The Frontier MFG Global Equity Fund returned -2.85%, net of fees, for the six-month period ending December 31, 2018, while the Frontier MFG Global Plus Fund (Institutional Class) returned -2.71%, net of fees, for the same time period. Both Funds outperformed the -9.10% return of their benchmark, the MSCI World Index (Net).

Global stocks fell in the six months to December after tighter U.S. monetary policy, tensions between China and the U.S., key resignations from the U.S. administration, and political uncertainty in Europe fanned doubts about the global economic outlook.

The Funds recorded a negative return for the period in U.S. dollars. The stocks that struggled most included the investments in Facebook, Kraft Heinz and Apple. Facebook's biggest slide occurred in July after management said slower revenue growth and higher costs would reduce profit margins from about 45% to about 35%. The decline persisted for the rest of the period as media reports attacked how top executives handled fake news, privacy issues and other incidents. Kraft Heinz's biggest tumble occurred in November when it said it had delayed cost cutting to support better sales growth during the third quarter. Apple tumbled over the last three months on concerns about the strength of sales of its latest devices.

Stocks that performed best included the investments in Starbucks, Yum! Brands and HCA Healthcare. Starbucks's biggest surge occurred in November on news that faster-than-expected sales growth of 4% in the Americas and 3% globally for the third quarter beat expectations, and the coffee chain said it would cut about 5% of the workers based in its headquarters in Seattle to reduce costs. Yum! Brands rose from July after revenue and profit for the second quarter outdid expectations, as they did for the third quarter. HCA rallied from July after the U.S. hospital chain reported higher-than-expected profits and revenue for the second quarter. It repeated the outperformance for the third quarter and raised guidance for the full year due to higher patient numbers and an increase in higher-paying procedures.

Fund Outlook and Strategy

While equity prices have fallen recently, we remain cautious because there are still many forces that could drive them lower still.

The pre-eminent worry for global stocks is that global monetary policy has further to tighten. The U.S. Federal Reserve is reducing the size of its balance sheet and has signalled another two rate increases in 2019, while the European Central Bank stopped expanding its balance sheet at the end of 2018. These reductions in central bank bond purchases present a risk to bond prices, which could flow through to equity prices.

This monetary tightening is occurring at a time when global economic growth has slowed and become less synchronised across the major economies. As well as tighter monetary policy, this slowing has been driven by heightened political uncertainties. In the U.S., the Republican Party's loss of control of the House of Representatives in the mid-term elections reduces President Donald Trump's control of Congress and might cause his actions to become more unpredictable at a time when the U.S.-China confrontation, international trade tensions and North Korea denuclearisation talks are ongoing. In Europe, many voters remain concerned about immigration and sluggish economic growth, resulting in elevated political risk.

Due to these risks, we held the cash position in the Funds at approximately 18% over the December quarter.

The Funds

Notwithstanding the uncertainty surrounding stock markets, we are confident about the long-term outlook for the investments selected for our portfolios and the portfolios' risk profile. Many of the stocks in the portfolio benefit from the following durable investment trends:

•  Consumer technology platforms: Leading digital platforms are well positioned to monetise new services and products even when they are not the originators of these items. Due to high switching costs and formidable barriers to entry, their entrenched positions are unlikely to be challenged in the foreseeable future.

•  Enterprise software: Established enterprise software vendors are capitalising on their incumbency. They typically operate in concentrated markets that have high barriers to entry, enjoy network effects and have loyal customers due to the high cost of switching out of their services. The shift to cloud computing creates an opportunity for them to expand their capabilities and win a greater share of business spending.

•  Healthcare and the dynamics of ageing populations: The healthcare sector enjoys favourable growth prospects due to rising patient numbers as developed populations age, higher expenditure in Western countries as more treatments are cultivated and the prospect that rising wealth in the emerging world will allow providers to target unmet healthcare needs in these countries.

•  The cashless society: Spending is shifting to cashless forms of payments such as credit cards, debit cards, electronic funds transfer and mobile payments. The explosion of smart and internet-connected devices will accelerate this shift the world over.

We retain confidence in the quality and long-term outlook for our investments and are comfortable with the Funds' overall risk profile and construction.

Yours sincerely,

Hamish Douglass
Portfolio Manager
MFG Asset Management

INVESTMENT HIGHLIGHTS

Growth of a $1,000,000 Investment (Unaudited)

*  12/28/11 commencement of operations.

Portfolio Total Return**

This chart assumes an initial gross investment of $1,000,000 made on 12/28/11 (commencement of operations). Returns shown include the reinvestment of all distributions. Past performance is not predictive of future results. Investment return and principal value will fluctuate so that shares, when redeemed, may be worth more or less than the original cost. In the absence of existing fee waivers, total return would be reduced. To receive current to the most recent month-end performance, please call 1-888-825-2100.

The MSCI World Index (Net) represents large and mid cap equities across 23 Developed Markets countries. The index covers approximately 85% of the free float-adjusted market capitalization in each country. The index does not reflect investment management fees, brokerage commissions and other expenses associated with investing in equity securities. A direct investment in the index is not possible.

Frontegra Asset Management, Inc. has contractually agreed through October 31, 2020, to waive its management fee and/or reimburse the Fund's operating expenses to the extent necessary to ensure that the Fund's total operating expenses (excluding taxes, interest, brokerage commissions, acquired fund fees and expenses and extraordinary expenses) do not exceed 0.80% of the Fund's average daily net assets. The expense ratios presented are based on the annualized expense ratios as reported in the Fund's current prospectus, which may differ from the expense ratios presented in the Fund's financial highlights.

**  The returns shown do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or the redemption of Fund shares.

INVESTMENT HIGHLIGHTS

Growth of a $1,000,000 Investment (Unaudited)

*  3/23/15 commencement of operations.

Portfolio Total Return**

This chart assumes an initial gross investment of $1,000,000 made on 3/23/15 (commencement of operations). Returns shown include the reinvestment of all distributions. Past performance is not predictive of future results. Investment return and principal value will fluctuate so that shares, when redeemed, may be worth more or less than the original cost. In the absence of existing fee waivers, total return would be reduced. To receive current to the most recent month-end performance, please call 1-888-825-2100.

The MSCI World Index (Net) represents large and mid cap equities across 23 Developed Markets countries. The index covers approximately 85% of the free float-adjusted market capitalization in each country. The index does not reflect investment management fees, brokerage commissions and other expenses associated with investing in equity securities. A direct investment in the index is not possible.

Frontegra Asset Management, Inc. has contractually agreed through October 31, 2020, to waive its management fee and/or reimburse the Fund's operating expenses to the extent necessary to ensure that the Fund's total operating expenses (excluding taxes, interest, brokerage commissions, acquired fund fees and expenses and extraordinary expenses) do not exceed 0.80% of the Fund's average daily net assets for the Institutional Class. The expense ratios presented are based on the annualized expense ratios as reported in the Fund's current prospectus, which may differ from the expense ratios presented in the Fund's financial highlights.

**  The returns shown do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or the redemption of Fund shares.

The above graph relates to Institutional Class shares of the Fund. Performance for Service Class shares will vary from the performance of the Institutional Class shares shown above due to differences in expenses.

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FRONTIER
MFG CORE INFRASTRUCTURE FUND
AND
FRONTIER
MFG SELECT INFRASTRUCTURE FUND

REPORT FROM MFG ASSET MANAGEMENT

Dear Fellow Shareholders:

The investment objective of the Frontier MFG Core Infrastructure Fund is long-term capital appreciation. The investment objective of the Frontier MFG Select Infrastructure Fund is to seek attractive risk-adjusted returns over the medium- to long-term, while reducing the risk of permanent capital loss. The objectives for both Funds are measured against the S&P Global Infrastructure Index.

Infrastructure assets offer investors protection from the impacts of inflation because their earnings generally have some direct linkage to inflation. Over time, the stable, reliable earnings of infrastructure assets are expected to lead to a combination of income and capital growth for investors.

The types of companies purchased in the Funds are generally natural monopolies that provide essential services to the community. The universe of infrastructure assets held in both Funds is made up of two main sectors:

•  Utilities: Utilities includes both regulated energy utilities and regulated water utilities. Utilities are typically subject to economic regulation. The terms of regulation typically require a utility to efficiently provide an essential service to the community and, in return, permit the utility to earn a fair rate of return on the capital it has invested in its operations. As a utility provides a basic necessity, such as energy or water, there is minimal fluctuation in demanded volumes in response to the economic cycle, while the price charged for the utility service can be adjusted with limited impact upon demanded volumes. As a result, the earnings of regulated utilities have been, and are expected to continue to be, stable irrespective of economic conditions.

•  Infrastructure: This includes airports, ports, toll roads and broadcast communications infrastructure. Regulation of infrastructure companies is generally less intensive than regulation of utilities and this allows companies to accrue the benefits of volume growth (i.e. the returns of infrastructure companies are linked to growth in passengers, vehicles or containers). As economies develop, grow and become more inter-dependent, we expect the underlying level of aviation, shipping and vehicle traffic to increase. As a result, the revenues and earnings derived by infrastructure assets are expected to grow.

If a company isn't either a regulated utility or an infrastructure asset per se, we require at least 75% of its earnings to be consistently derived from either regulated assets or infrastructure assets before it can be included in the Funds.

Performance Review

The Frontier MFG Core Infrastructure Fund, Institutional Class, returned -3.12%, net of fees, for the six-month period ending December 31, 2018. The Fund's return outperformed the -6.64% return of its benchmark, the S&P Global Infrastructure Index. For the year, the Fund returned -6.61%, net of fees, compared to the benchmark's return of -9.50%.

The Frontier MFG Select Infrastructure Fund, Institutional Class, returned -4.25%, net of fees, since the Fund's inception on July 2, 2018, through December 31, 2018. The Fund's return outperformed the -6.30% return of its benchmark, the S&P Global Infrastructure Index for the same time period.

Global stocks fell in the six months to December after tighter U.S. monetary policy, tensions between China and the U.S., key resignations from the U.S. administration, and political uncertainty in Europe fanned doubts about the global economic outlook.

Both Funds recorded a negative return for the period. The biggest detractor was Atlantia, the share price of which fell 28% in the Core Infrastructure Fund over the six months ending December 31, 2018, and 30% since the inception of the Select Infrastructure Fund, following the August collapse of a bridge on a tolled road in Genoa. The bridge that collapsed was a tolled section of the A10 motorway that was operated under a concession contract by Autostrade per l'Italia, an 88% owned subsidiary of Atlantia of Italy. The newly formed

left-right populist Italian government blamed Atlantia for being derelict in its duties to maintain the bridge. The government appears to have commenced a process that could lead to it revoking the single concession that governs Autostrade per l'Italia's toll-road network in Italy. We removed Atlantia from the portfolios following internal analysis, including meetings with Italian legal and political experts, that led us to conclude that the range of financial outcomes that Atlantia faces is wide. Thus, we no longer believe the financial returns to shareholders are as reliable and predictable as we require of stocks held in the strategy given our central tenet of capital preservation. Aeroports de Paris shed 14% in the Core Infrastructure Fund and 16% in the Select Infrastructure Fund after the French government said the law to sell its controlling interest in the Paris airport operator wouldn't be ready until the end of the northern winter and it was considering selling its ownership on a piecemeal basis rather than to a strategic buyer.

American Tower contributed significantly to both Funds, jumping more than 10% after the owner of wireless communications towers raised guidance for fiscal 2018 and reported higher-than-expected earnings and sales figures for the third quarter.

Specific to the Core Infrastructure Fund, PG&E lost 8.4% on concerns that its electrical utility subsidiary might be liable for starting deadly bushfires in California. Duke Energy added 11% after third-quarter earnings beat expectations after heat across the southern U.S. boosted demand for energy to help people cool down.

In the Select Infrastructure Fund, the Aena share price fell 11% as Spain's new Socialist government suspended the release of the company's "master plan", creating uncertainty over the company's dividend-payout ratio post 2020. In addition, the company said it expected only a 2% increase in passenger traffic in Spain next year, the smallest increase since 2013, due to concerns that uncertainty over Brexit would reduce arrivals of UK tourists who represented over 17% of total passengers through Spain's airports. Stocks that contributed significantly included U.S. investments in Eversource Energy and Crown Castle International. Eversource gained 11% after the power utility announced operating revenue for the third quarter that beat estimates and management indicated that it would increase capital expenditure guidance for the full-year result. Crown Castle rose 2.0% after the U.S. cell-tower operator reported higher-than-expected second-quarter earnings, due largely to site growth, and boosted full-year guidance.

Movements in stocks are in local currency.

Portfolio Outlook and Strategy

The strategies seek to provide investors with attractive risk-adjusted returns from the infrastructure asset class by investing in a portfolio of listed infrastructure companies that meet our strict definition of infrastructure. We believe that infrastructure assets, with requisite earnings reliability and a linkage of earnings to inflation, offer attractive, long-term investment propositions. Furthermore, given the predictable nature of earnings and the structural linkage of those earnings to inflation, investment returns generated by infrastructure assets are different from standard asset classes and offer investors valuable diversification when included in an investment portfolio. In the current uncertain economic and investment climate, the reliable financial performance of infrastructure investments makes them particularly attractive and an investment in listed infrastructure can be expected to reward patient investors with a three- to five-year time frame.

Sincerely,

Gerald Stack
Portfolio Manager
MFG Asset Management

INVESTMENT HIGHLIGHTS

Growth of a $100,000 Investment (Unaudited)

*  1/18/12 commencement of operations.

Portfolio Total Return**

This chart assumes an initial gross investment of $100,000 made on 1/18/12 (commencement of operations). Returns shown include the reinvestment of all distributions. Past performance is not predictive of future results. Investment return and principal value will fluctuate so that shares, when redeemed, may be worth more or less than the original cost. In the absence of existing fee waivers, total return would be reduced. To receive current to the most recent month-end performance, please call 1-888-825-2100.

The MSCI World Index (Net) represents large and mid cap equities across 23 Developed Markets countries and covers approximately 85% of the free float-adjusted market capitalization in each country. The S&P Global Infrastructure Index is a global developed markets infrastructure and utilities benchmark. Neither index reflects investment management fees, brokerage commissions or other expenses associated with investing in equity securities. A direct investment in an index is not possible.

Frontegra Asset Management, Inc. has contractually agreed through October 31, 2020, to waive its management fee and/or reimburse the Fund's operating expenses to the extent necessary to ensure that the Fund's total operating expenses (excluding taxes, interest, brokerage commissions, acquired fund fees and expenses and extraordinary expenses) do not exceed 0.70% of the Fund's average daily net assets for the Institutional Class. The expense ratios presented are based on the annualized expense ratios as reported in the Fund's current prospectus, which may differ from the expense ratios presented in the Fund's financial highlights.

** The returns shown do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or the redemption of Fund shares.

The above graph relates to Institutional Class shares of the Fund. Performance for Service Class shares will vary from the performance of the Institutional Class shares shown above due to differences in expenses.

INVESTMENT HIGHLIGHTS

Growth of a $1,000,000 Investment (Unaudited)

*  7/2/18 commencement of operations.

Portfolio Total Return**

This chart assumes an initial gross investment of $1,000,000 made on 7/2/18 (commencement of operations). Returns shown include the reinvestment of all distributions. Past performance is not predictive of future results. Investment return and principal value will fluctuate so that shares, when redeemed, may be worth more or less than the original cost. In the absence of existing fee waivers, total return would be reduced. To receive current to the most recent month-end performance, please call 1-888-825-2100.

The MSCI World Index (Net) represents large and mid cap equities across 23 Developed Markets countries and covers approximately 85% of the free float-adjusted market capitalization in each country. The S&P Global Infrastructure Index is a global developed markets infrastructure and utilities benchmark. Neither index reflects investment management fees, brokerage commissions or other expenses associated with investing in equity securities. A direct investment in an index is not possible.

Frontegra Asset Management, Inc. has contractually agreed through October 31, 2020, to waive its management fee and/or reimburse the Fund's operating expenses to the extent necessary to ensure that the Fund's total operating expenses (excluding taxes, interest, brokerage commissions, acquired fund fees and expenses and extraordinary expenses) do not exceed 0.80% of the Fund's average daily net assets. The expense ratios presented are based on the annualized expense ratios as reported in the Fund's current prospectus, which may differ from the expense ratios presented in the Fund's financial highlights.

** The returns shown do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or the redemption of Fund shares.

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FRONTIER
TIMPANI SMALL CAP GROWTH FUND

REPORT FROM TIMPANI CAPITAL MANAGEMENT LLC

Dear Fellow Shareholders:

The Frontier Timpani Small Cap Growth Fund strives to achieve capital appreciation by investing in a diversified portfolio of growth companies with small market capitalizations. Timpani seeks to:

•  Invest in companies where growth is robust, sustainable and underestimated by the market.

•  Conduct fundamental research that provides unique insights into the growth gap that exists between market expectations and a company's true growth rate.

•  Manage risk by continuously evaluating the size of the growth gap relative to market expectations and monitoring market sentiment.

•  Act on new relevant incremental data points, both positive and negative, in an effort to exploit investor biases.

For the six months ended December 31, 2018, the Frontier Timpani Small Cap Growth Fund, Institutional Class, outperformed its benchmark, the Russell 2000^® Growth Index, returning -15.62%, net of fees, compared to -17.33% for the benchmark. For the year, the Fund returned -0.08%, net of fees, compared to -9.31% for the benchmark.

Performance Review

During the period, the Fund posted negative returns but outperformed its benchmark. It was definitely a tale of two quarters. The third quarter recorded strong returns and fundamental momentum was rewarded, however, the fourth quarter was the opposite — valuations compressed across the board regardless of fundamental performance. Investors are most concerned with the U.S. economic outlook. To the extent economic growth fears materialize, the market will increasingly appreciate companies that are less dependent on macroeconomic growth including many of the secular growers in the Timpani portfolio. Thus, we continue to be optimistic about our positioning.

Detailed attribution analysis of the portfolio suggests stock selection drove most of the upside while sector allocation was a modest positive during the period. Health Care and Materials & Processing stock selection were the biggest contributors to the upside while Consumer Discretionary stock selection was the largest detractor.

The top two individual contributors came from two different sectors. Leading the way was Health Care holding, Vericel Corporation. Its regenerative tissue repair technology is gaining momentum with severe burn victims and patients with knee injuries. This momentum is showing up in the numbers. For instance, the September quarter results showed 58% organic year-over-year revenue growth, a figure that exceeded consensus expectations by 24%. Another winner was Technology stock, Five9. Its cloud-based call center communication software is being embraced in the marketplace, especially at the enterprise level. Company execution has been consistently strong for several quarters including the September quarter where organic year-over-year revenue growth was 30%, exceeding consensus expectations by 6%. Technology stock, USA Technologies, was the weakest performer. In September, it negatively surprised investors by announcing it was delaying the filing of its Form 10-K due to an internal investigation of its accounting practices. While the fundamental momentum here appears strong, this incremental news was alarming, and the position size was reduced as a result. Technology stock, Varonis Systems, was another laggard. Early in the period, it reported an uncharacteristically weak earnings report. The position size was reduced as a result.

Regarding sector positioning, we ended the period with notable overweights in Technology and Health Care and underweights in Financial Services and Producer Durables. The portfolio remains tilted toward secular growth stocks that are less dependent on the growth of the overall economy. We believe this is especially prudent now given the macroeconomic murkiness that exists.

Investing Environment and Outlook

During the period, the whole stock market was weak, however, small cap stocks were hit especially hard. Whether it be driven by monetary policy at the Federal Reserve, tariffs, U.S. government in-fighting, or international economic sluggishness, investors are worried about U.S. economic growth. These fears have caused valuation multiples to contract across the board.

Despite these fears, we like the set-up for the overall stock market from current levels. We think macro fundamentals are fragile but will prove better than feared and that most of the damage to stocks has already been done. We believe we are likely several quarters away from a recession, thus, this recent compression in valuation multiples is premature. For the next few quarters, we believe the most likely scenario is a low-growth, non-recessionary economic environment. Because of the scarcity of growth, this backdrop should enhance valuations for secular growth stocks overall, including those in Timpani's portfolio.

In summary, we are optimistic about Timpani's prospects and remain committed to our long-term approach of investing in companies with fundamental momentum. We seek companies with a sustained, underestimated growth profile and overlay that approach with an unemotional, value-added sell discipline. We believe this process creates the most value for our clients and mutual fund shareholders over time.

Thank you for your continued interest, support, and trust.

Sincerely,

Brandon Nelson, CFA
Chief Investment Officer
Timpani Capital Management LLC

INVESTMENT HIGHLIGHTS

Growth of a $100,000 Investment (Unaudited)

*  3/23/11 commencement of operations.

Portfolio Total Return**

This chart assumes an initial gross investment of $100,000 made on 3/23/11. Returns shown include the reinvestment of all distributions. Past performance is not predictive of future results. Investment return and principal value will fluctuate so that shares, when redeemed, may be worth more or less than the original cost. In the absence of fee waivers, total return would be reduced. To receive current to the most recent month-end performance, please call 1-888-825-2100.

The Russell 2000^® Growth Index measures the performance of the small-cap growth segment of the U.S. equity universe. The index does not reflect investment management fees, brokerage commissions and other expenses associated with investing in equity securities. A direct investment in the index is not possible.

Timpani Capital Management LLC has contractually agreed through October 31, 2020, to waive its management fee and/or reimburse the Fund's operating expenses to the extent necessary to ensure that the Fund's total operating expenses (excluding taxes, interest, brokerage commissions, acquired fund fees and expenses and extraordinary expenses) do not exceed 1.10% of the Fund's average daily net assets of the Institutional Class. The expense ratios presented are based on the annualized expense ratios as reported in the Fund's current prospectus, which may differ from the expense ratios presented in the Fund's financial highlights.

**  The returns shown do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or the redemption of Fund shares.

The above graph relates to Institutional Class shares of the Fund. Performance for Service Class and Class Y shares will vary from the performance of the Institutional Class shares shown above due to differences in expenses.

FRONTIER
PHOCAS SMALL CAP VALUE FUND

REPORT FROM PHOCAS FINANCIAL CORPORATION

Dear Fellow Shareholders:

The Frontier Phocas Small Cap Value Fund strives to achieve capital appreciation by investing in a diversified portfolio of equity securities of companies with small market capitalizations. The Fund's performance is measured against the Russell 2000^® Value Index.

Performance Review

During the six-month period ended December 31, 2018, the Frontier Phocas Small Cap Value Fund, Institutional Class, returned -20.39%, net of fees, compared to the -17.36% return of the benchmark, the Russell 2000^® Value Index (the "Benchmark" or the "Index"). For the calendar year, the Fund's Institutional Class shares returned -17.52%, net of fees, compared to -12.86% for the Index.

Portfolio Review and Strategy

The most significant underperforming sectors for the six-month period were Financials, Industrials, and Consumer Discretionary. The Financials sector was impacted largely by the community banks group. The Fund's holdings in bank stocks are over-weighted in the stronger regions of the country including Virginia, Texas, California, and the Southeast. While demand for loans is quite strong in these areas, banks here often must pay more for deposits, and a flattening yield curve could pressure their net interest margins. Interestingly, despite their much stronger profitability and growth prospects, many banks in these areas now trade at significant discounts to banks in far less attractive regions of the country. Also, worth noting is that the smallest, most illiquid banks in the Benchmark significantly outperformed the others. Banks of this size are too small for the Fund to establish a significant investment position.

Within Industrials, Wesco Aircraft Holdings, an industrial parts supplier to aircraft manufacturers, experienced weak stock performance in the period due to recent profit margin decline and their announcement that in 2019 they will be putting money into initiatives to increase efficiencies and to grow their business. ASGN Inc., provider of professional and information technology employee staffing, was also an underperformer during this period despite strong business trends that surpassed analysts' expectations. We believe this company's stock got caught up, unjustifiably so, in the wave of selling that decimated many small cap stocks.

The Consumer Discretionary sector was impacted by poor performance from TopBuild, provider of insulation and insulation services to the residential and commercial construction industry. TopBuild's stock seems to be a victim of investors shooting first and asking questions later. While revenues are growing nicely and profit margins are expanding, investors became worried that the higher interest rates impacting residential housing would result in a slowdown in demand for insulation. Management has strategies to grow profits if demand slows but investors didn't seem to believe them or much care in 2018.

Real Estate was a notable outperformer for the six-month period. Jernigan Capital's stock rose in a down market thanks to investors seeking out defensive self-storage facility operators, but also because Jernigan is doing well financing others who are building self-storage facilities. Facilitating the stock's boost has been the company's seasoned management spending time educating investors about this small, relatively new publicly traded REIT. The Health Care sector performed well versus the Benchmark mostly due to strong stock performance from biohazard vaccine provider, Emergent BioSolutions. The company is growing quickly partly due to acquisition, but it is also seeing strong demand from the U.S. government for its Biothrax vaccine. Further, its other products are becoming in greater demand from European nations aiming to defend their citizens from potentially new bioweapons. Cash was also additive to performance for the six-month period.

During the fourth quarter selloff, we took the opportunity to strengthen the Fund's bank holdings by initiating new positions in top notch Pacific Premier Bancorp (Los Angeles) and Pinnacle Financial Partners (Tennessee and Carolinas). We also added to Eagle Bancorp (Washington DC) and F.N.B. (Pennsylvania and Carolinas). We sold six banks to fund these purchases. In Real Estate, we sold our lodging holdings Hudson Pacific Properties and Chatham Lodging and purchased Dallas-based office property owner Tier REIT. We also

replaced data center provider CoreSite Realty with its peer, QTS Realty Trust. In Technology, we started new positions in MAXIMUS (technology consulting company to the U.S. government) and electronics distributor SYNNEX, while selling Conduent. Consumer Discretionary received two new companies, Ruth's Hospitality Group and Hilton Grand Vacations, which replaced SeaWorld Entertainment where we took significant profits. We reduced our exposure to services in the Energy sector, selling both US Silica Holdings and Superior Energy Services, replacing them with Colorado-based exploration and production company Jagged Peak Energy.

Thank you for your continued support.

INVESTMENT HIGHLIGHTS

Growth of a $100,000 Investment (Unaudited)

Portfolio Total Return*

This chart assumes an initial gross investment of $100,000 made on 12/31/08. Returns shown include the reinvestment of all distributions. Past performance is not predictive of future results. Investment return and principal value will fluctuate so that shares, when redeemed, may be worth more or less than the original cost. In the absence of fee waivers, total return would be reduced. Effective October 8, 2010, Phocas Financial Corp. ("Phocas") became subadviser to the Fund and Frontegra Asset Management, Inc. became adviser to the Fund. Prior to October 8, 2010, Phocas served as adviser to the Fund. To receive current to the most recent month-end performance, please call 1-888-825-2100.

The Russell 2000^® Value Index measures the performance of those Russell 2000^® companies with lower price-to-book ratios and lower forecasted growth values. The index does not reflect investment management fees, brokerage commissions and other expenses associated with investing in equity securities. A direct investment in the index is not possible.

Frontegra Asset Management, Inc. has contractually agreed through October 31, 2020, to waive its management fee and/or reimburse the Fund's operating expenses to the extent necessary to ensure that the Fund's total operating expenses (excluding taxes, interest, brokerage commissions, acquired fund fees and expenses and extraordinary expenses) do not exceed 0.95% of the Fund's average daily net assets of the Institutional Class. The expense ratios presented are based on the annualized expense ratios as reported in the Fund's current prospectus, which may differ from the expense ratios presented in the Fund's financial highlights.

* The returns shown do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or the redemption of Fund shares.

The above graph relates to Institutional Class shares of the Fund. Performance for Service Class shares will vary from the performance of the Institutional Class shares shown above due to differences in expenses.

Frontier Funds

EXPENSE EXAMPLE

December 31, 2018 (Unaudited)

As a shareholder of a mutual fund, you incur two types of costs: (1) transaction costs, including redemption fees, and (2) ongoing costs, including management fees, distribution and/or service (12b-1) fees and other fund expenses. Although the Funds charge no sales loads, you will be assessed fees for outgoing wire transfers, returned checks and stop payment orders at prevailing rates charged by U.S. Bancorp Fund Services, LLC, the Funds' transfer agent. If you request that a redemption be made by wire transfer, currently the Funds' transfer agent charges a $15.00 fee. A redemption fee of 2.00% of the then current value of the shares redeemed may be imposed on certain redemptions of shares made within 30 days of purchase for the Frontier MFG Global Equity, Frontier MFG Global Plus, Frontier MFG Core Infrastructure and Frontier MFG Select Infrastructure Funds.

This Example is intended to help you understand your ongoing costs (in dollars) of investing in the Funds and to compare these costs with the ongoing costs of investing in other mutual funds. The Example is based on an investment of $1,000 invested at the beginning of the period and held for the entire period (7/1/18 – 12/31/18).

Actual Expenses

The first line of the table on the following page for each Fund provides information about actual account values and actual expenses. The Example includes management fees, registration fees, fee waivers/reimbursements and other expenses. However, the Example does not include portfolio trading commissions and related expenses and other extraordinary expenses as determined under generally accepted accounting principles. You may use the information in this line, together with the amount you invested, to estimate the expenses that you paid over the period. Simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then multiply the result by the number in the first line under the heading entitled "Expenses Paid During the Period" to estimate the expenses you paid on your account during this period.

Hypothetical Example for Comparison Purposes

The second line of the table for each Fund provides information about hypothetical account values and hypothetical expenses based on each of the Fund's actual expense ratios and an assumed rate of return of 5% per year before expenses, which is not the actual return. The hypothetical account values and expenses may not be used to estimate the actual ending account balance or expenses you paid for the period. You may use this information to compare the ongoing costs of investing in each of the Funds and other funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds.

Please note that the expenses shown in the table are meant to highlight your ongoing costs only and do not reflect any transactional costs, such as redemption fees. Therefore, the second line of the table is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds. In addition, if these transactional costs were included, your costs could have been higher.

Frontier Funds

EXPENSE EXAMPLE (continued)

December 31, 2018 (Unaudited)

*  Expenses are equal to each Fund's annualized expense ratio indicated above, multiplied by the average account value over the period, multiplied by 184/365 to reflect the one-half year period.

Frontier Funds

EXPENSE EXAMPLE (continued)

December 31, 2018 (Unaudited)

*  Expenses are equal to each Fund's annualized expense ratio indicated above, multiplied by the average account value over the period, multiplied by 184/365 to reflect the one-half year period.

**  Actual expenses are equal to the Fund's annualized expense ratio of 0.80% multiplied by the average account value over the period, multiplied by 183/365 to reflect the most recent fiscal period end since the MFG Select Infrastructure Fund commenced operations on July 2, 2018.

***  Hypothetical expenses are equal to the Fund's annualized expense ratio of 0.80% multiplied by the average account value over the period commencing July 1, 2018, multiplied by 184/365 to reflect information had the MFG Select Infrastructure Fund been in operation for the entire fiscal half year.

Frontier MFG Global Equity Fund

SCHEDULE OF INVESTMENTS

December 31, 2018 (Unaudited)

(a)  Non-Income Producing.

PORTFOLIO DIVERSIFICATION

Frontier MFG Global Plus Fund

SCHEDULE OF INVESTMENTS

December 31, 2018 (Unaudited)

(a)  Non-Income Producing.

PORTFOLIO DIVERSIFICATION

Frontier MFG Core Infrastructure Fund

SCHEDULE OF INVESTMENTS

December 31, 2018 (Unaudited)

Frontier MFG Core Infrastructure Fund

SCHEDULE OF INVESTMENTS (continued)

December 31, 2018 (Unaudited)

Frontier MFG Core Infrastructure Fund

SCHEDULE OF INVESTMENTS (continued)

December 31, 2018 (Unaudited)

(a)  Non-Income Producing.

PORTFOLIO DIVERSIFICATION

Frontier MFG Select Infrastructure Fund

SCHEDULE OF INVESTMENTS

December 31, 2018 (Unaudited)

Frontier MFG Select Infrastructure Fund

SCHEDULE OF INVESTMENTS (continued)

December 31, 2018 (Unaudited)