Official announcements by Standard and Poor's have confirmed that the group is all set to list Warren Buffett's Berkshire Hathaway Inc. to its S&P 500 Stock Index, as the firm prepares to takeover Burlington Northern Santa Fe Corp., the railroad operator.

On the news, Class B shares of Berkshire surged by $5.40, or 7.9%, to $73.40 in after-hours. The Class A shares of the company, however, which was not split, on Tuesday closed after losing $1.449 at $101,751. In after hours, however, they hiked by 8.1% to $110,000.

The announcement by S&P has come after Berkshire's 50-for-1 split of the B shares, which happened just last week, with the aim to make it simpler for shareholders of Burlington Northern to exchange their shares for those of Berkshire in a tax-free swap, instead of accepting cash.

"The split provided more liquidity and index investors have to buy the stock, which both can boost the shares. The addition to the index is something I don't think Warren Buffett was lobbying for, but is certainly something he would have wanted", said Steven Check, Chief Investment Officer of Check Capital Management Inc.