Top 20 Rank: 4
Rank among: Insurance: Property and Casualty: 1
"It takes 20 years to build a reputation, and five minutes to ruin it." The man who coined this aphorism, Warren Buffett, knows a thing or two about great reputations: His company, Berkshire Hathaway, has long been a fixture on our list of America's Most Admired Companies.Buffett burnished his reputation even more in June 2006, when he announced plans to give away the bulk of his $40 billion fortune, much of it to the Bill & Melinda Gates Foundation.
More: See how Berkshire rates in 8 key areas.