Stocks Wobble at the Flat Line

Updated from 12:23 p.m. EDT

After opening higher, U.S. stocks cautiously meandered about the baseline Monday as investors kept an eye on unusual moves from a couple of big-time pharmaceutical companies, an increase in oil prices and bearish forward-looking indicators from the Conference Board.

The Dow Jones Industrial Average was losing 15 points at 11,481, and the S&P 500 lost about half a point to 1261. The Nasdaq shed 2 points to 2281.

Providing a drag for the major indices, Merck (MRK Quote) and Schering-Plough (SGP Quote), originally slated to report Monday morning, delayed their statements until after the market close to provide an update from a study on their joint venture drug, Vytorin.

The results of the Vytorin study identified a potential cancer risk in certain patients and said the drug was no more effective than a placebo at reducing the risk of major cardiovascular events. Merck lost 3.9%, and Schering-Plough tumbled 11%.

Elsewhere in pharmaceuticals, Swiss pharmaceutical company Roche made a $43.7 billion offer for the rest of Genentech (DNA Quote). Roche is already a 56% shareholder in the maker of cancer drug Avastin. Genentech shares jumped 13% on the news.

In technology, Yahoo! (YHOO Quote) was another headliner, as the company agreed to give investor Carl Icahn, who wanted the Internet portal owner to work a deal with Microsoft (MSFT Quote), a seat on its board. Yahoo! stock was edging downward.

XM Satellite Radio (XMSR Quote) said it added 322,000 new subscribers in the second quarter, a 17% year-over-year increase. The company also announced a $400 million offering of senior notes to help refinance debt pending an intended merger with Sirius Satellite Ratio (SIRI Quote). Shares of both XM and Sirius were on the rise.