BRK is one of the bluest of the blue chips and number 3 in the Fortune 500, so it logically is hitting new highs. But, not understanding your adding of fractional shares. That can't be done with BRK.A or BRK.B, unless you are characterizing the B shares as fractional shares. The only way one can accumulate fractional shares of any stock would be through a Dividend Reinvestment Plan (DRIP), where dividends are reinvested yielding some fractional shares. But, since BRK has never paid a dividend, there can be no fractional shares.