Monday brought strong gains for the stock market, with the ongoing success of the just-started earnings season helping to support major-market indexes even as they remain near their all-time record highs. Although the Dow and S&P 500 weren't able to close above their previous high-water marks, sentiment among investors appears to be quite positive as early reports from the financial sector haven't been as bad as many had feared. Moreover, big gains on the day from Whiting Petroleum (NYSE:WLL), Advanced Micro Devices (NASDAQ:AMD), and AeroVironment (NASDAQ:AVAV) helped improve the mood on Wall Street as well.

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Whiting Petroleum jumped 8% as the oil and gas exploration and production company scored a coup by acquiring peer Kodiak Oil & Gas (NYSE: KOG) in a $6 billion deal. With the deal involving entirely stock, it's unusual that Whiting shares would be able to hold their gains, but in fact, Whiting shares rose by a greater percentage than Kodiak's today. Despite some disappointment among Kodiak investors that they couldn't command an even greater premium to where the stock had traded recently, many are optimistic that Whiting Petroleum's long-term prospects are even more favorable now that it will have a commanding presence in the key Bakken Shale play. Moreover, with the opportunity to cut costs even further by joining forces, the new Whiting could reap even bigger advantages from its Bakken stake.

Source: AMD.

Advanced Micro Devices climbed 6% as investors look forward to the company's quarterly report later this week. AMD has long labored in the shadow of larger chipmakers, failing to attain a leadership role either in PC microprocessors or in mobile devices. Yet over the holiday season, AMD achieved a measure of success by specializing in game-console chips, and investors hope that that strategy will yield positive results. Moreover, with reports that PC demand could be higher than expected this quarter, AMD could share in a rebound if desktops powered by AMD chips turn out to be what enterprise customers choose to replace aging machines.

Source: AeroVironment.

AeroVironment gained another 6%, adding to its gains from last week following a favorable earnings report. The maker of unmanned aerial vehicles built on the increasing popularity of drones, which saw a 42% jump in sales in its fiscal fourth quarter. Increases to revenue guidance also point to AeroVironment's belief that the positive trend favoring drones will continue. Given the stock's current valuation, investors are counting on that upward trajectory proving to be true, and any disappointment on the sales front could send AeroVironment's shares crashing back to earth.

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