Stocks at highs, but pros question catalyst

IBM increases buyback; Analyst warns

Though the Dow Jones industrial average and S&P 500 index closed at record highs Tuesday, some professional traders questioned whether the gains are healthy, especially considering IBM gave the blue chips its biggest boost with its announcement.

IBM's stock, which also helped drive the S&P's rally, jumped roughly 2.7 percent to $182.12 after the technology company's board of directors approved another $15 billion stock repurchase program.

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