(Reuters) -MicroStrategy shares briefly surged on Monday before faltering to end nearly unchanged, after the software company and bitcoin stockpiler was selected to join the tech-heavy Nasdaq 100 index, further brightening the prospects of the stock. The $25.7 trillion index that houses the largest non-financial companies will now gain indirect exposure to bitcoin via MicroStrategy, which holds $44 billion worth of the digital currency on its balance sheet, about 2% of the total supply of the world's largest cryptocurrency. The prospect of more buying from funds that track the Nasdaq 100 could further boost MicroStrategy's stock that has surged nearly 550% this year alongside a jump in the bitcoin price.