But many stocks missed out. Merck & Co., Inc. (NYSE: MRK ) was the Dow's biggest loser, dropping the better part of 1% today on news that the FDA is investigating diabetes drugs to see if there might be a link to potential pancreatic inflammation and pre-cancerous changes. Although many companies make such drugs, Merck's Januvia has been particularly successful, stepping up to provide a much-needed revenue boost when the company lost patent protection on its Singulair asthma medication. Any threat to that success could pose a big problem for Merck going forward. The Home Depot, Inc. (NYSE: HD ) fell three-quarters of a percent. Yesterday's retail sales number seemed like a reasonably strong one, but reading into the details revealed some concerns about the strength of the consumer-led recovery.