Warren Buffett loves to concentrate his Berkshire Hathaway’s invested capital in a small number of top ideas and, after buying back Berkshire Hathaway stock, his top idea is the world’s most valuable company, Apple, which accounts for close to 48% of Berkshire’s invested assets. Warren Buffett at Berkshire Hathaway’s annual meeting of shareholders on May 8, 2023 Sean Williams for The Motley Fool: As of the closing bell on June 16, 2023, the 915,560,382 shares of Apple stock held by Berkshire Hathaway equates to a market value of $169.3 billion. This works out to 47.8% of the invested assets of Berkshire’s investment portfolio and is nearly 40 percentage points higher than the second-largest holding by portfolio weighting, Bank of America…