NightHawk shareholders will receive $6.50 per share in cash from Virtual Radiologic, representing a 100% premium to the stock's closing price on Friday. The transaction is expected to be completed in the first quarter of 2011, the companies said. Shares of NightHawk are surging by $3.14, or 96.5%, to $6.39. Volume topped 7.45 million shares, compared to the average daily share volume of 71,000. Elsewhere, BioFuel Energy ( BIOF) shares are rallying by 63 cents, or 37.5%, to $2.31 after the company said Friday it has entered into a six-month $19.4 million bridge loan agreement with Greenlight Capital and an affiliate of Third Point LLC. The bridge loan was used to repay $17.9 million in working capital loans. Volume topped 2.49 million shares, compared to the average daily share volume of 218,000. LDK Solar ( LDK) shares are jumping by $1.33, or 15%, to $10.18 after the company said it has borrowed $8.9 billion from the China Development Bank to fund its expansion efforts. Volume topped 12 million shares, compared to the average daily share volume of 2.97 million. Shares of Rainmaker Systems ( RMKR) are spiking late in Monday's session, rising by 40 cents, or 37%, to $1.48 after the company said in a regulatory filing that it has entered into a statement of work under its vendor services agreement with Microsoft ( MSFT) to provide the company with global telesales and chat sales services. Rainmaker said the statement of work covers the U.S., Europe and the Middle East, and Asia-Pacific regions and has an initial three-year term. Services are set to begin on Nov. 1, Rainmaker said. Volume topped 170,000 shares, compared to the average daily share volume of 9,000. -- Written by Robert Holmes in Boston. >To contact the writer of this article, click here: Robert Holmes. >To follow Robert Holmes on Twitter, go to http://twitter.com/RobTheStreet. >To submit a news tip, send an email to: firstname.lastname@example.org.