$14 billion in assets with more than 1,000 individual stock positions. Taking over when Magellan was a small fund, Lynch had no restrictions on what assets he could buy (other than laws, such as an SEC-enforced federal law that prohibits investment company funds that are registered as "diversified" from holding more than 5% of total portfolio assets in a single company at time of purchase ). He focused on individual companies rather than any overarching strategy, starting with large US companies and gradually shifting emphasis to smaller and international stocks. From 1977 until 1990, the Magellan fund averaged a 29.2% annual return and as of 2003 had the best 20-year return of any mutual fund ever. Lynch found successes in a broad range of stocks from different industries; according to Beating the Street his most profitable picks were Fannie Mae, Ford, Philip Morris, MCI, Volvo, General Electric, General Public Utilities, Student Loan Marketing, Kemper, and Lowe's. Investment philosophy Lynch has written (with co-author John Rothchild) three texts on investing: One Up on Wall Street (), Beating the Street (), and Learn to Earn. The last-named book was written for beginning investors of all ages, mainly teenagers. In essence, One Up served as theory while Beating the Street is application. One Up lays out Lynch's investment technique including chapters devoted to stock classifications, the two-minute drill, famous numbers, and designing a portfolio. Most of Beating the Street consists of an extensive stock by stock discussion of Lynch's 1992 Barron's Magazine selections, essentially providing an illustration of the concepts previously discussed. As such, both books represent study material for investors of any knowledge level or ability. Lynch also wrote a series of investment articles for Worth magazine that expand on many of the concepts and companies mentioned in the books.Lynch coined some of the best-known mantras of modern individual investing strategies. His most famous investment principle is, "invest in what you know," popularizing the economic concept of "local knowledge". Since most people tend to become expert in certain fields, applying this basic "invest in what you know" principle helps individual investors find good undervalued stocks. Lynch uses this principle as a starting point for investors. He has also often said that the individual investor is potentially more capable of making money from stocks than a fund manager, because they are able to spot good investments in their day-to-day lives before Wall Street.