I'd think this and everything Buffet used to do is obviously outdated. Any simplistic indicator or metric won't be more accurate than what a current market cap for the company is as financial companies, with state of the art tools, researchers and experience can determine what is accurate with far more efficiency than Buffet or any simple metric ever could. If they realise there's inaccuracy in a market cap somewhere, and there's reason to believe that the market cap will change in some direction, they will take the profit from it until there's nothing to take and market cap will be accurate again according to their calculations. Even if in some cases they might be wrong, they will be more accurate in the long run as any usual metric due to law of large numbers. Essentially when trying to use any indicators or metrics here you are playing poker against people who have far more information about the cards compared to what you have.