Updated from 4:03 p.m. EST

Stocks ended a choppy session mixed Thursday, but the Dow Jones Industrial Average closed back above the psychologically relevant 10,000 mark.

The indices opened higher as a strong quarter from Hewlett-Packard ( HWP) and a further reduction in jobless claims cheered investors, but the major averages turned negative within minutes of the opening bell. Stocks spent most of the rest of the session higher before pulling back in the last hour.

The Dow ended up 12 points, or 0.1%, to 10,002. The Nasdaq lost 16 points, or 0.9%, to 1843, and the S&P 500 was off 2 points at 1116.

After the bell Wednesday, Hewlett-Packard said it earned, on a pro forma basis, 29 cents a share on revenue of $11.4 billion in its fiscal first quarter, both handily beating estimates that had been compiled only 10 days earlier. The company's chief executive said the results showed Hewlett's designs on Compaq Computer ( CPQ) were being pursued from a posture of strength. But shares of H-P finished down 10 cents to $20.88.

The weekly data on jobless claims also contributed to the buoyant mood. The claims showed first-time applications for unemployment benefits fell by 8,000 to 373,000 in the latest week. Another report showed business inventories fell by 0.4% in December, roughly in line with estimates.

Tyco ( TYC) fell 7.4% to $26.75 after executives appeared to back away from a plan to split the conglomerate into five separate companies. In remarks to analysts Wednesday, CEO Dennis Kozlowski implied the company would proceed with the plan according to market conditions, which lately have been less than favorable to Tyco. Its shares are off more than 40% this year.

Brocade ( BRCD) lost 7% to $32.64, one day after the company met analysts' first-quarter consensus earnings estimate on stronger-than-expected sales and said it was comfortable with Wall Street's forecast for the next fiscal quarter. For the first quarter, the company earned 5 cents a share, meeting estimates.

Sprint PCS ( PCS) dropped $1.42, or 12.2%, to $10.20, and several other wireless stocks were lower as liquidity concerns spread throughout the sector.

Shares of copier manufacturer Xerox ( XRX) fell on bearish comments from analysts regarding the company's stock price, urging investors to take profits. The stock sold off accordingly, closing down 80 cents, or 7.5%, to $9.81

Qwest ( Q), off 12.8%, and Tyco were the most active stocks on the Big Board. Juniper ( JNPR), which lost 15.7%, WorldCom ( WCOM), which lost 2 cents, and Cisco ( CSCO), falling 2 cents, led the Nasdaq's list of top volume movers.

Nortel Networks ( NT) was one of several chipmakers to lose ground, falling 39 cents, or 6.4%, to $5.72.

Treasury bonds were mixed, with the 10-year note trading up 8/32 to 99 13/32, yielding 4.95%. Shorter-term notes were lower.

Overseas markets were mainly higher, with London's FTSE 100 and Germany's Xetra DAX both showing roughly 1% gains. Japan's Nikkei ended with a gain of about 1.1%.