Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: National Semiconductor (NYSE: NSM) popped 72% in intraday trading today after announcing a deal to be taken over by Texas Instruments (NYSE: TXN).

So what: National Semi has agreed to sell itself to TI for $25 a share in cash, 78% higher than yesterday's closing price. Both companies' boards have approved the deal, and it is expected to close in six to nine months.

Now what: The deal is likely to pass antitrust scrutiny because of the fragmented nature of the analog semi industry, which also includes STMicroelectronics NV (NYSE: STM), Analog Devices (NYSE: ADI), and Linear Technology (Nasdaq: LLTC). National Semi has 12,000 products that should benefit from sales and marketing synergies with TI's 30,000-product lineup. Acquisitions often fail to meet expectations, and TI arguably paid too much. However, National Semi holders should be grateful they're getting paid in cash instead of shares.

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