Stocks fell Thursday after Standard & Poor’s cut the debt ratings of General Motors Corp. and Ford Motor Co. to junk status, undermining the market’s confidence and dealing a blow to major automakers.

The Dow Jones Industrial Average fell 44.26, or 0.4 percent, to 10,340.38. Much of the loss could be attributed to GM’s falling stock price. The Standard & Poor’s 500 Index was down 3.02, or 0.3 percent, at 1,172.63. The Nasdaq Composite Index lost 0.43, or 0.02 percent, to 1,961.80.

S & P; cited intense global competition and waning sales of the automakers’ most profitable vehicles, pulling General Motors down 5.7 percent to $30.92 and Ford down 5.7 percent to $9.58. The downgrades, which dragged the rest of the market, came one day after stocks surged in response to billionaire investor Kirk Kerkorian’s offer to more than double his stake in GM.

Among local movers, SeeBeyond Technology Corp. rose 4.3 percent to $2.89 after the Monrovia-based company announced that its board of directors approved a repurchase program of up to $10 million of common stock over the next 24 months. The stock repurchase program will be funded using working capital.

On the down side, shares of 3-D Systems Corp. lost 15.6 percent to close at $16.47 after the Valencia-based designer of three dimensional printing and manufacturing systems reported net income of $1.2 million (5 cents per diluted share) on revenue of $30.4 million for the first quarter ended March 31. The analyst consensus estimate for earnings was 11 cents per share on revenue of $32.3 million.

Big 5 Sporting Goods Corp. fell 6 percent to $22.99 after the El Segundo-based sporting goods retailer, reported net income, after Wednesday’s closing bell, of $7.2 million (32 cents per diluted share) for the first quarter ended April 3, missing analysts’ consensus estimate of 33 cents per share due to modest sales and higher expenses.

And Magnetek Inc. slipped 3.2 percent to $2.12 after the stock of the L.A.-based maker of digital power products was downgraded to “underperform” from “market perform” by analyst J. Steven Smigie at Raymond James. On Wednesday, shares of Magnetek plunged more than 44 percent after the company was ordered to pay $23.4 million to end an inventor’s lawsuit over electronic ballasts used in fluorescent lamps.