Apple ( AAPL) plunged $16.57, 10.7%, to $139.07 on sluggish iPod sales and a disappointing forecast for the current quarter. Apple posted a first-quarter profit of $1.58 billion, or $1.76 a share, compared with profit of $1 billion, or $1.14 a share, a year ago. Revenue for the quarter was $9.6 billion, compared with $7.1 billion a year ago. Analysts polled by Thomson Financial were expecting EPS of $1.62 a share on revenue of $9.46 billion. For the second quarter, Apple guided for revenue of $6.8 billion and earnings of 94 cents a share. Analysts were expecting revenue of $6.98 billion and EPS of $1.09. The company said iPod sales grew 5% last quarter, compared with 50% in the year-ago quarter. Intel ( INTC) and its rival AMD ( AMD) also fared well as investors favored the chip sector. Shares of Intel rose $1.35, or 7.3%, to $19.98, while AMD gained 74 cents, or 10.8%, to $7.57. And shares of bond insurer Ambac ( ABK) continued clawing their way back from the precipitous drop they took last week, even after yesterday's report of an enormous fourth-quarter loss , which was followed today by Goldman Sachs slashing its price target to $10 from $14. Regardless, Ambac shares lately took back another 27% to $10.12. MBIA ( MBI), another bond insurer, was adding 13.6%. First Cash Financial Services ( FCFS), an Arlington, Texas, pawnbroker, plummeted to new lows, losing 34.1% to $9.28, on Tuesday evening's report of a weak fourth quarter. The company posted adjusted earnings of $5.7 million, or 18 cents a share, vs. $9.7 million, or 27 cents a share, in 2006. Analysts polled by Thomson Financial were expecting 38 cents a share. To make matters worse, First Cash Financial lowered guidance for 2008 to $1.17 a share to $1.20 a share. The Street is looking for $1.51. Meanwhile, bond insurers Security Capital Assurance ( SCA) and Ambac ( ABK), which have recently been pummeled by mounting concerns about their viability, recovered a bit on the possibility of further capital infusions or other strategic alternatives. Shares of Hamilton, Bermuda-based Security Capital Assurance jumped 76.3% to $3.79, and New York-based Ambac rallied 71.9% to $13.70. Elsewhere, California bank Downey Financial ( DSL) set aside $218.4 million to cover bad loans in the fourth quarter, vaulting from credit-loss provisions of $81.6 million last quarter and $200,000 last year. In large part due to that, the bank swung to a fourth-quarter loss of $108.8 million, or $3.90 a share, compared with a year-earlier profit of $1.87 a share. Wall Street was seeking a 6-cent loss per share. First Midwest Bancorp's ( FMBI) fourth-quarter loss, panning out at 11 cents a share, also reverses a year-ago profit. Taking heavy blame here is the dwindling value of the bank's investments in asset-backed collateralized debt securities, without which First Midwest would have earned 56 cents a share. Still, Downey shares were jumping 17.8% to $30.30, and First Midwest was up 3.9% to $27.03.