After weeks of small and steady moves, stocks are back to wild daily swings again. Yesterday's terrible trading session was followed by an upbeat day: The Dow Jones Industrial Average (DJINDICES:^DJI) is up 0.9% as of 3:25 p.m. EST, and the S&P 500 (SNPINDEX:^GSPC) has climbed 1.2%. There wasn't a lot of economic news, but a big buyout in the PC business had investors buying again.

Computer maker Dell (NASDAQ:DELL.DL) announced a $24.4 billion deal to go private, paying shareholders $13.65 per share. Michael Dell and Silver Lake Partners are the lead investors, and Microsoft is throwing in a $2 billion loan as well.

This opens up an interesting competitive landscape in the PC market. Dell will now be less shackled by Wall Street's quarterly expectations, but private companies often don't have the same resources as their public rivals -- something Hewlett-Packard (NYSE:HPQ) was quick to point out today. HP sees the move as a negative for Dell customers, saying Dell won't be able to invest in innovation and development as it has before.

Investors have pushed HP 3% higher on Dell's news today, but I don't think it does much to change the landscape of the PC business. Both companies need to improve their products and find ways to expand beyond the traditional PC business to survive. At least PCs have today to see a bright future.

Another company moving the Dow higher today is UnitedHealth Group (NYSE:UNH), which is up 3.6% on the day. It was nothing more than an analyst upgrade at Goldman Sachs that had investors giddy today. The company's price target was bumped up to $66 from $57 on beliefs that health reforms would drive confidence in managed-care stocks. A few years ago, you may not have expected the health care bill to be such a boon for insurance companies, but there's a reason insurance stocks didn't plummet when it passed, and there's now more hope that it will drive earnings.

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