Qualcomm's management rejected Broadcom's raised offer of $121 billion to buy the company, though it opened up talks with its rival.
Qualcomm was down 1.31% at $61.60 per share.
Broadcom has made several advances to buy out its smaller rival in the past year. Last November, Qualcomm fended off another bid by Broadcom to acquire the company for $70 per share, valuing Qualcomm at $105 billion. Qualcomm's board has maintained that the company is worth more.
Qualcomm has also been hit with setbacks. It is fighting a patent infringement case with Apple, and it has been subject to intense scrutiny by European regulators, which slapped Qualcomm with a $1.2 billion fine for alleged anticompetitive practices last month.
Qualcomm is scheduled to hold a shareholder meeting on March 6. Broadcom is expected to put its own nominees up for election to Qualcomm's board of directors, Reuters reported.
Qualcomm's stock was down 5.34% for the year. Broadcom's stock was trading at $229.04 a share, and slid 14.26% for the year.