Author Bio Dave mainly covers financial stocks, primarily banks and asset managers, and investment planning. He's covered mutual funds and institutional investments for Pensions & Investments, personal finance for S&P, and money markets and bonds for Crane Data. Dave has been a Fool since 2014. Follow @dhkovaleski Warren Buffett, the chairman and CEO of Berkshire Hathaway, has held Moody's (NYSE:MCO) in his portfolio for 20 years, as of October. The credit rating and data analytics company is his fifth-longest-held position. Any stock that the Oracle of Omaha has held for 20 years probably deserves your attention. If Buffett's stamp of approval alone is not a good enough reason for you to invest in this stock -- and it shouldn't be -- letʻs take a deeper dive to see why Moody's is worth an investment.