Berkshire Hathaway’s Class A shares trade under the stock ticker BRK.A.
Berkshire Hathaway is a multinational holding company led for decades by Warren Buffett. Its Class A shares are famous for their exceptionally high per-share price, because the company has never carried out a conventional stock split. Each Class A share also has substantially greater voting and economic rights than a Class B share.
Berkshire created Class B shares in 1996, partly to make ownership more accessible to investors who could not afford a Class A share. Class B shares trade under BRK.B and represent a much smaller economic interest. The two classes refer to the same corporation but are not interchangeable tickers.
A high share price does not by itself prove that a company has the highest market capitalization. Market capitalization depends on share price multiplied by the number of shares outstanding. Berkshire’s market value reflects its insurance operations, investments, railroads, utilities, and numerous operating businesses.