Onyx Pharmaceuticals, Inc. (Nasdaq: ONXX) ticked higher Monday following headlines that big names like Pfizer (NYSE: PFE), Novartis (NYSE: NVS), and AstraZeneca (NYSE: AZN) might all be mulling a bid for the company. Speculation follows a $120 per share offer made by Amgen Inc. (Nasdaq: AMGN) that Onyx disclosed on July 1st.

Bloomberg said that all three of the aforementioned suitors have entered confidentiality agreements and have tapped advisors ahead of first-round bidding.

Onyx management previously snubbed Amgen's bid and Amgen is waiting to hear back from Onyx before making another go.

Shares of Onyx have been trading above the $120 Amgen bid over the last few weeks on investors speculation that a stronger offer would come in for the company.

Onyx shares are up 2.8 percent Monday.