Standard & Poor's said it would maintain its triple-A ratings on bond insurers Ambac ( ABK) and MBIA ( MBI). Shares of Ambac were jumping 15.1% to $12.33, and MBIA was up 22.3% to $14.89. Shares of video-games company Take-Two ( TTWO) soared $9.53, or 54.9%, to $26.89 after its larger rival Electronic Arts ( ERTS) made a $2-billion, or $26-a-share, unsolicited offer. After Take-Two's management rejected the bid , EA turned hostile, taking its offer to Take-Two's shareholders. EA's stock fell $2.60, or 5.2%, to $47.14. Shares of Genentech's ( DNA) were climbing 8% after the FDA late Friday approved the use of Avastin in breast cancer. The accelerated approval was based on the benefits to progression-free survival -- the delayed growth of tumors -- when the drug is added to chemotherapy. Avastin, currently a treatment for colorectal and non-small-cell lung cancers, is expected to receive full approval in breast cancer when the company submits data from two more studies. The approval came as something of a surprise, since an FDA panel voted 5-4 in December to recommend against the breast cancer approval. Genentech shares were adding $6 to $77.60. Heading in the opposite direction, small-cap Immtech Pharmaceuticals ( IMM) plunged 45% after the company said it would discontinue the development program for pafuramidine, a late-stage investigational therapy for a type of pneumonia in AIDS patients. The action is in response to instances of abnormal kidney function, which resulted in hospitalization of several study participants. Following the discontinuation of the study, Immtech won't receive further payments from Strativa, a division of Par Pharmaceuticals ( PRX) that has commercialization rights to the drug candidate. Immtech shares tanked 90 cents to $1.10. On the losing side was FirstFed Financial ( FED), which fell 4% to $32.80 after the company increased its total nonperforming assets. Meanwhile, Houston's Tesco ( TESO), which creates technology solutions for the upstream energy industry, jumped 13.3% to $23.45 on fourth-quarter earnings. The company posted income of $6.6 million, or 18 cents a share, vs. $10.5 million, or 29 cents a share, in 2006. This year's fourth-quarter earnings include a $1.2 million loss related to expiration of its Turnkey E&P warrants. Analysts polled by Thomson Financial were looking for EPS of 17 cents, excluding items. Shares of Marvell Technology ( MRVL) gained 65 cents, or 5.9%, to $11.77 after a report in Barron's said the company could see its shares double in two years as its chips get integrated into new products. Shares of ethanol company Verenium ( VRNM) got pounded down 12.5% to $3.08 after the Cambridge, Mass., firm announced a $54 million convertible debt offering. Verenium is issuing senior convertible notes maturing April 1, 2012, and exchanging $16.7 million of these notes for $18.5 million of existing 5.5% convertible senior notes. The company said it was raising the money for general working capital purposes.