Each weekday, TheStreet.com Ratings compiles a list of the top 10 stocks in five categories -- fast-growth, all-around value, large-cap, mid-cap and small-cap -- and publishes these lists on the Ratings section of our Web site.The rankings are based on our ratings, which assess risk-adjusted returns, as well as other criteria specific to the type of stock. We update the lists at the end of the business day on the basis of information available at the close of the previous trading session. The following day, we publish an article that takes a closer look at the ratings of the stocks on one of the lists. Today we look at large-cap stocks. These are companies with market capitalizations of over $10 billion that rank in the top 50% of all stocks rated by our proprietary quantitative model, which looks at more than 62 factors. In addition, the stocks must be followed by at least one financial analyst who posts estimates on IBES. They are ordered by their potential to appreciate. Defense contractor Lockheed Martin ( LMT) tops this week's list. The company has had a buy rating since November 2004 thanks to strong financial performance, growing demand for its commercial satellites and advanced defense systems, and an expanding product base. The company has increasingly sought civilian contracts in air traffic management and IT outsourcing as it seeks to lessen its reliance on the U.S. government. Lockheed has also focused on international expansion through acquisitions and contracts with India and Pakistan, countries that are ramping up their military spending.