The ongoing credit crisis continued to crop up in various incarnations and make for a rollercoaster-like day, with the financial sector getting pulled from a morning jump to an afternoon slump that seemed to be easing just before a finish in the red. The NYSE Financial Sector Index closed off 0.3% to 8,181.6, and the KBW Bank Index ended down 0.1% to 88.79. One of the day's more positive developments was the progression of another Federal Reserve effort to inject liquidity into the market -- the first of four planned auctions allowing banks to borrow below the discount rate for 28 days. Out of 93 U.S. banks bidding $61.6 billion, the Fed today accepted $20 billion worth. But putting a damper on things was new data from mortgage-research company RealtyTrac, which said that November foreclosures surged 68% from a year ago. This comes a day after the Fed proposed a plan to protect consumers from "unfair or deceptive" marketing practices that may have led to many of those foreclosures. On thin ice at Standard & Poor's, meanwhile, were bond insurers Ambac ( ABK), MBIA ( MBI) and Security Capital Assurance ( SCA). S&P gave them all a negative outlook, which means they're in danger of losing their AAA ratings. That might have far-reaching implications, since it could put into question the ratings of all the securities each has insured. Ambac recovered to close up 1.8% at $27.46, but MBIA lost 2.5% and SCA gave up 1.5%.