Energy Future Holdings Corp., the power producer taken private in the biggest-ever leveraged buyout, moved a step closer to a bankruptcy plan after a key creditor neared a reorganization agreement, Bloomberg News reported on Saturday. Fidelity Investments, which holds some of Energy Future’s $45.6 billion of debt, is hashing out terms for the plan, which is being discussed by the power producer’s management, two groups of unsecured creditors and the private-equity owners who took it over. The investment firm’s participation in negotiations is crucial because it enables Energy Future to enter bankruptcy with a pre-arranged plan that would reduce the time it takes to reorganize in chapter 11. Fidelity has been a holdout among creditors to the company formerly known as TXU Corp., which KKR & Co., TPG Capital and Goldman Sachs Capital Partners bought for $48 billion in 2007.