By Rex Crum, MarketWatch

SAN FRANCISCO (MarketWatch) -- Semiconductor stocks mostly rose Tuesday as the sector reacted to Texas Instruments Inc.'s deal to buy National Semiconductor Corp. for $6.5 billion.

Announced late Monday, TI's (TXN) offer, which has been approved by the boards of both companies, values National Semi (NSM) at $25 a share. Investors sent National Semi's shares up more than 71%, to $24.06 in early trading.

The deal marks a major consolidation in analog chips, where TI and National Semi both have major market shares.

Among other chip stocks, big gains came from Intersil Corp. (ISIL), up $1.22, or 10%, to $13.35; Semtech Corp. (SMTC), higher by $1.50, or 6.2%, to $25.86, and On Semiconductor Corp. (ONNN), up 48 cents, or 5%, to $10.16.

The Philadelphia Semiconductor Index (SOX) was up by 1.8%, while the Nasdaq Composite Index (RIXF) fell 3.8 points to 2,785.

Also Tuesday, shares of Apple Inc. (AAPL) fell $3, or about 1%, to $338.10. The Nasdaq OMX said it was rebalancing the Nasdaq-100 Index (NDX) and would lower Apple's weighting to about 12% from more than 20% -- reflecting the big increase in Apple's share price over the last two years -- effective with the open of the markets on May 2.

Among other tech stocks, gains came from Dell Inc. (DELL) as well as Dow Jones Industrial Average components Microsoft Corp. (MSFT) and Hewlett-Packard Co. (HPQ)

 
 
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