"This complementary transaction will position the combined company as a global communications leader with an impressive portfolio of technologies and products", Hock Tan, resident and chief executive officer of Broadcom, said in a statement Monday.
Broadcom is up 2.31% to $279.95 and Qualcomm is up 4.57% to $64.63.
Since publication Broadcom and Qualcomm have confirmed the offer, with Broadcom disclosing that the bid of $70 a share is made up of $60 cash and $10 in Broadcom shares.
Qualcomm said it would review the proposal but the San Diego-based company is inclined to reject the bid as too low and fraught with risk that regulators may reject it or take too long to approve it, people familiar with the matter told Reuters.
Any deal struck between the two companies would face intense regulatory scrutiny, especially in China, which is home to expanding rivals.More news: Ezekiel Elliott fighting for more than playing time: 'I'm not an abuser'
"We would not make this offer if we were not confident that our common global customers would embrace the proposed combination, and we do not anticipate any material antitrust or other regulatory issues that would extend the normal timetable for closing a transaction of this nature".
"Broadcom's proposal is compelling for stockholders and stakeholders in both companies".
Qualcomm is more vulnerable to a takeover now because its shares have been held down by a patent dispute with Apple, as well as concerns it may have to raise its own $38 billion bid for NXP Semiconductors NV that it made a year ago.
Broadcom, Qualcomm and NXP together would have control over modems, Wi-Fi, GPS and near-field communications chips, a strong position that could concern customers such as Apple and Samsung Electronics Co Ltd because of the bargaining power such a combined company could have to raise prices.
Broadcom said if the deal is approved, it expected a combined company to have revenues of about $51 billion.
The acquisition offer comes just days after President Trump announced that Broadcom would be moving its headquarters to the United States from Singapore and as Qualcomm is embroiled in a fierce legal battle with Apple.