(CNBC) — U.S. stocks rallied on Monday, lifting the S&P 500 to a record and clearing its 2014 loss, as investors embraced activity on the M&A front and continued to disregard lackluster economic data as largely due to winter weather.

Mergers and acquisitions had RF Micro Devices agreeing to acquire TriQuint Semiconductor for about $1.6 billion, while Men’s Wearhouse hiked its cash tender offer for Jos. A. Bank Clothiers.

“Maybe stocks are not overpriced at these levels if you have big players coming in and still doing deals,” said Chris Gaffney, senior market strategist at EverBank.

“Bad weather is going to impact housing and retail sales; once it’s spring and the weather is not so bad, we’ll see a true reading on the economy,” Gaffeny added.

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