Berkshire Hathaway Inc . (NYSE:BRKa)'s Class B shares (NYSE:BRK.B) continued their upward trend for a third consecutive day on Friday, with a modest gain of 0.37%, closing at $346.34. This comes amidst a broadly positive market, where the S&P 500 Index and Dow Jones Industrial Average advanced to 4,308.50 and 33,407.58 respectively.