They say that most bull markets end with a final bout of exuberance, and that certainly looks like what might be happening with the stock market these days. The Dow Jones Industrials (^DJI 0.69%) have risen seven straight days, setting new records for each of the past five sessions as the average added another 50 points today. The broader market also rose, although small-cap U.S. stocks as well as foreign stock markets generally didn't perform as well.

The Dow's biggest gainers were Boeing (BA -0.76%) and Merck (MRK -0.05%). For Boeing, which rose more than 2%, continued confidence from company executives about the airplane manufacturer's long-term prospects amid huge demand for commercial aircraft showed that Boeing is focused squarely on its future, keeping in perspective recent woes with the 787 Dreamliner. In addition, the company has finally found the problem behind the Dreamliner's battery issues and believes it has a safe and reliable solution to fix the problem permanently.

Meanwhile, Merck rose 1.6% despite releasing the data behind its negative findings from a study on niacin-drug Tredaptive. Still, the company has other promising candidates in its pipeline, including folic acid-based cancer drug vinafolide. Moreover, as investors start to get nervous about the length of the bull market, Merck has a certain resistance to bear markets because of the need for its products.

Beyond the Dow, Zynga (ZNGA) soared more than 10% on rumors that Yahoo! might buy out the company. Given the fast pace of changes at Yahoo! since Marissa Mayer took over, one Wall Street analyst believes that boosting its social-media presence is part of Yahoo!'s strategy and that Zynga is just one of many promising candidates in the space that would make for a promising acquisition.

Finally, Genworth Financial (GNW 1.50%) rose almost 7% after positive comments from Barron's over the weekend. The article noted that recovering housing prices have really helped the company's mortgage-insurance business, and as government agencies get out of the insurance business, Genworth and its peers have more room to take advantage of the recovery. The shares have already climbed substantially, but a true return to normal levels of home-price appreciation would backstop the premiums that Genworth charges to customers.