Credit and liquidity concerns swirling around Bear Stearns ( BSC) sent the stock to new lows and pulled the financial sector down with it. The brokerage house wobbled as early morning options trading saw heavy volume in puts being written at low prices. Bear Stearns was selling shares at $53.99, but had been as low as $50.48, a decline of 16%. Elsewhere CBRE Realty Finance ( CBF) reported a fourth-quarter adjusted loss of $11.9 million, or 39 cents a share, compared to last year's profit for the same period of 19 cents a share. Not only that, the Hartford, Conn.-based commercial real estate specialty finance company announced that it hired Goldman Sachs ( GS) as its financial adviser to assist with its strategic and operational initiatives. CBRE traded down 6.9% to $3.90. Chipmaker Sigma Designs ( SIGM) shares were getting trounced after the company cut its first-quarter revenue forecast, saying a problem in its orders caused it to ship more products than called for by the market's actual demand. Sigma fell $4.16, or 16.5%, to $21.10. Web services provider GSI Commerce ( GSIC) jumped after an upgrade by Jefferies based on valuation and a belief that e-commerce market fundamentals remain "OK."The stock was up 97 cents, or 8.5%, to $12.34. Shares of air medical transportation services and systems provider Air Methods ( AIRM) climbed 16.4% to $46.11. The Denver-based company announced fourth-quarter revenue of $122.6 million, up 58% from the year-ago period. Income rose to $4.8 million, or 38 cents a share, from $1.2 million, or 10 cents a share, a year ago. Analysts polled by Thomson Financial were looking for 33 cents a share. Atlanta's Cumulus Media ( CMLS), which operates FM and AM radio station clusters, rose 27.6% to $6.25. The company disclosed in a filing with the Securities and Exchange Commission today that its lenders consented to an amendment to its credit agreement permitting a merger with an investment group led by CEO Lewis Dickey and an affiliate of Merrill Lynch Global Private Equity.