Warren Buffett's 'phenomenal' advice to GM CEO backfired for Berkshire despite the stock tripling. Avoid his big mistake

J. Countess/ Getty Images; Kayla Bartkowski/ Getty Images Moneywise and Yahoo Finance LLC may earn commission or revenue through links in the content below. Warren Buffett once put General Motors CEO Mary Barra on the spot with a question. Would she run the company differently if she didn't have to report earnings every three months? When Barra said no, Buffett offered advice she still calls (1) "phenomenal." Top Picks Jeff Bezos backs a platform that lets anyone invest in rental homes for as little as $100 — 6 ways to build wealth like a landlord without actually being one A record 45% of central banks plan to grow gold reserves — and many investors are following suit.