Core Insights - Warren Buffett is entering his final week as CEO of Berkshire Hathaway, a company he has transformed from a struggling textile manufacturer into a conglomerate valued at over $1 trillion [2] - Buffett's net worth is estimated at $151 billion, primarily from his Class A shares in Berkshire Hathaway, ranking him 10 on the Bloomberg Billionaires Index [2] - Despite his success, Buffett has referred to Berkshire Hathaway as "the dumbest stock I ever bought," highlighting a significant mistake that cost him hundreds of billions [3][10] Company History and Transformation - Buffett acquired control of Berkshire Hathaway in 1965, initially viewing it as a cheap stock in a declining textile business [5][6] - The company had been closing mills and buying back its stock, which led Buffett to believe he could profit from a tender offer [6][9] - After a disappointing tender offer price, Buffett decided to buy control of the company and eventually shifted its focus away from textiles [9][10] Lessons Learned - Buffett acknowledges that investing in a poor business can be detrimental, stating that if he had invested in a good business instead of textiles, Berkshire Hathaway would be worth twice as much today, estimating a potential value of $200 billion [11][12] - He emphasizes the importance of recognizing when to exit a bad business, stating that it took him 20 years to abandon the textile operations [12][17] - The experience taught Buffett that it is better to invest in good businesses at fair prices rather than cheap businesses with poor economics [16][20] Business Philosophy - Buffett's management philosophy diverges from conventional business school teachings, as he prefers to retain underperforming businesses unless they are permanently losing money or facing major issues [22][23] - He believes that the difficulty of a business does not equate to its potential for success, advocating for a focus on simpler, more manageable investments [20][21] - Buffett credits his business partner, Charlie Munger, for influencing his investment approach and acknowledges that he could have avoided many mistakes by heeding Munger's advice [24]