Buffett likes insurance companies because of the cash flows they generate, allowing Berkshire Hathaway to invest hundreds of billions of dollars of "other people's money." In Buffett's letter to shareholders last year, he elaborated on his love of insurance, saying the products "will never be obsolete, and sales volume will generally increase along with both economic growth and inflation." Progressive is a company that thrives in all environments because of its stellar underwriting ability and is a top insurance stock you can add today that can bring both stability and growth to your portfolio for years to come.