"Investors must never forget that their expenses are Wall Street's income," the billionaire investor told his shareholders. : Warren Buffett owned up to a major mistake, trumpeted Berkshire Hathaway's past successes, and drew a line between his long-term shareholders and the meme-stock crowd in his annual letter on Saturday. The billionaire investor said Berkshire's focus is boosting operating earnings and making large, high-quality acquisitions. His conglomerate "met neither goal" in 2020 as its operating earnings slumped 9% and it failed to close any major deals, he said.