Spring is in the air, as the stock market opened the month with a nice boost thanks to positive economic data from both the U.S. and China. Investors are squarely focused on the prospects for the economy, as a long recession followed by a tepid recovery has been a disappointment to many. Yet at the same time, if growth prospects get too strong, the possibility that the Federal Reserve could start to tighten up on its accommodative monetary policy could lurch the markets into a decline as well. Walking that tightrope has been a challenge, but with the Dow Jones Industrials (INDEX: ^DJI) closing at their highest levels since late 2007, optimism ruled the day.

But a few stocks didn't join in on the fun. Let's take a closer look at three of them.

Cisco Systems (Nasdaq: CSCO), down 0.8%
Many of the biggest tech companies in the market have already announced their earnings for the quarter. But with Cisco having another week to wait before its May 9 earnings release, investors may be wondering whether the company can keep up the pace of some of its competitors.

Analysts are expecting reasonable growth from the networking giant, with a projected 11% rise in earnings per share on a revenue increase of about 6.5%. But the big question is whether favorable results from F5 Networks and Juniper Networks (NYSE: JNPR) came at Cisco's expense or indicate strength throughout the sector. We'll have to wait until a week from tomorrow to find out.

Caterpillar (NYSE: CAT), down 0.6%
On a day of positive economic data, you might expect Caterpillar to join the Dow's party today. But the equipment maker is running into some labor problems that could threaten its renewed emphasis on its domestic business.

More than 800 workers at a Caterpillar Illinois plant went on strike this morning after rejecting a six-year labor contract. The workers' concerns include wage freezes and higher health-care premiums, while Caterpillar argues that the offer is competitive. Although the company has brought in replacement workers, Caterpillar has to make sure that labor problems don't hurt the huge demand that has helped the business do so well in recent years.

Pfizer (NYSE: PFE), down 0.5%
For its part, Pfizer announced its first-quarter earnings today, and as everyone expected, patent expirations are leaving their mark on the company.

Pfizer reported that Lipitor sales dropped by about $1 billion during the quarter, although it cited how deals to offer big rebates and discounts helped it maintain far more market share than it would have without such big measures. Although it beat earnings expectations for the quarter, Pfizer cut its full-year profit projections to below where analysts had pegged them. It will be interesting to see how the Lipitor experience affects both the rest of Pfizer's drug lines as well as the many other companies dealing with patent expirations.

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