Investing.com -- Yardeni Research acknowledged in a note Wednesday that September has a reputation as the weakest month for stocks, but argued that any weakness this time could set up a buying opportunity ahead of a year-end rally.

The firm wrote that "everyone in the stock market knows that September is the cruelest month for stocks." But it added that when September proves difficult, "it tends to create buying opportunities for a year-end rally that often starts in October."

Furthermore, firm noted that investors are anxious about rising global bond yields, elevated oil prices and pressure on central banks to raise rates.

Yardeni said it shares the concerns of so-called bond vigilantes but is not convinced yields are, or will soon be, prohibitively high, arguing they are simply normalizing after a long period of abnormally low levels following the financial crisis.

With U.S. nominal GDP up 6.6% year over year in the second quarter against a 10-year Treasury yield near 4.80%, the firm said strong demand should emerge if the yield hits 5%, including from Treasury Secretary Scott Bessent.

Yardeni pointed to a run of firm data as evidence the economy remains healthy, including July JOLTS figures showing a labor market at full employment, Redbook same-store sales up 8.7%, an eighth straight month of manufacturing expansion, and surging data center construction. The Atlanta Fed’s GDPNow model shows third-quarter growth of 4.8%.