Big contract wins and corporate dealmaking were some of the catalysts behind Monday's most actively traded stocks.
Shares of Alnylam Pharmaceuticals jumped more than 50% after the tiny drug developer said it inked a deal with Swiss drug giant Roche to develop Alnylam's gene-silencing technology in order to fight diseases.
The deal, which has Roche making an upfront payment of $338 million with the potential for future milestone payments of $1 billion, is one of the largest in the nascent but promising research area. Alnylam rival Sirna Therapeutics was acquired by Merck earlier this year for more than $1.1 billion.
Green energy outfit First Solar surged to new all-time highs on Monday after the company said it signed new contracts which should result in future sales of more than $1.2 billion. Tiny energy company Beacon Power, which is developing "flywheel technology" in order to harness kinetic energy, also saw shares move higher on Monday.
Schnitzer Steel Industries gained after the steelmaker reported strong quarterly results on Monday morning. The positive results came in ahead of an earnings update from basic materials giant Alcoa set for release Monday after the close of trading.
Sigmatel shares saw big gains after the specialty chipmaker boosted second-quarter guidance, citing improved sales across the board. The Austin, Tex.-based company now expects second-quarter sales in a range of $30 to $31 million, compared with previous guidance of $24 to $28 million.
"We believe we have strong momentum going into the third quarter and are looking forward to sharing more good news during our second quarter conference call," Chief Executive Phil Pompa said in a prepared statement. Sigmatel said it will host the call later this week.
Peter Kang is a markets writer at CNBC.com and can be reached at email@example.com.