US Stocks in Focus (NSM, AAPL, QCOR, CBST, ISIL, DMND, CREE, TGP, KYN)

The companies whose shares are actively trading in Tuesday's morning session include National Semiconductor, Apple, Questcor, Cubist, Intersil, Diamond Foods, Cree and Teekay LNG.

Gainers

Shares of National Semiconductor (NYSE:NSM) were surged 71 percent after Texas Instruments (NYSE:TXN) agreed to buy the company for $6.5 billion, or $25 per share. Shares were trading up by $10 at $24.07.

Shares of Questcor Pharmaceuticals (NASDAQ:QCOR) jumped $3.10 or 21 percent to $18.02 after its preliminary first quarter revenue topped Street view.

Shares of Cubist Pharmaceuticals (NASDAQ:CBST) soared $4.15, or 16 percent, to $29.40, after it settled a patent dispute with Teva (NASDAQ:TEVA).

Shares of Intersil (NASDAQ: ISIL) soared 10 percent to $13.35 as the TI-National Semi deal boosted chip stocks.

Shares of Diamond Foods (NASDAQ:DMND) advanced 10 percent to $62.90 after it agreed to buy Pringles business from Procter & Gamble Co. (NYSE:PG).

Losers

Shares of Apple (NASDAQ:AAPL) fell more than 1 percent after Wall Street Journal reported that Nasdaq plans to slash Apple's weighting in the Nasdaq-100 Index to about 12.3 percent from 20.49 percent.

Shares of Cree Inc. (NASDAQ:CREE) sank 4 percent to $43.90 after it cut its quarterly revenue forecast due to lower sales of LED chips and components.

Shares of Kayne Anderson MLP Investment Co. (NYSE:KYN) declined 5 percent to $30.57 after it priced its public offering of common stock at a discount to yesterday's closing price.

Shares of Teekay LNG Partners (NYSE:TGP) shares were down 5 percent to $38.54 after it priced its public offering of common stock at a discount to yesterday's closing price.