KKR & Co., Goldman Sachs Capital Partners and TPG Capital, the firms that led the $48 billion buyout of Energy Future Holdings Corp. in 2007, are fighting to receive barely 3 percent of their initial investment when the power generator files for bankruptcy as soon as this month, Bloomberg News reported yesterday. Negotiations with senior creditors including Leon Black’s Apollo Global Management LLC and Centerbridge Capital Partners LLC, which are poised to seize control of the former TXU Corp., were at a crucial juncture yesterday when agreements that allow them to view nonpublic information to foster talks expire. A proposal disclosed last week that wasn’t accepted would have given the company’s owners as little as $270 million. KKR, Goldman and TPG took Dallas-based Energy Future private in the largest leveraged buyout in history, an investment that was predicated on rising gas prices. Instead, they fell as the development of hydraulic fracturing created a surge in U.S. gas supplies, triggering 10 straight quarterly losses at the company since 2011 and leading Warren Buffett to say his $2 billion investment in Energy Future bonds was “a big mistake.” Energy Future is due to make about $270 million in interest payments Nov. 1 — cash that senior creditors want the company to retain to boost their recoveries in a bankruptcy. A filing would be the 12th-largest in the U.S. and the fifth biggest non-financial corporate ever, according to the UCLA-LoPucki Bankruptcy Research Database, which ranks companies by assets.