TORONTO (Reuters) - The Toronto Stock Exchange's main index finished nearly flat yesterday, pressured by weak energy shares, while BCE Inc. was hammered by concerns that a court decision could put an end to its buy-out.

Shares of BCE, Canada's biggest telecom company, slumped C$4.48, or 12.1 percent, to C$32.64 after a Quebec court backed debtholders who said that the buyout deal was unfair to them. The transaction, worth C$34.8 billion ($35.2 billion), is the world's largest leveraged buy-out.

BCE stock was halted by the TSX in the afternoon, pending clarification of the status of orders. The exchange said there had been a service disruption for about 45 minutes in the morning, which caused "data integrity concerns".

The telecom company's stock was the most actively traded by far at 26.3 million shares.

The S&P/TSX composite index eked out a tiny gain of 1.99 points, or 0.01 percent, to 14,792.36 with all but three of its 10 sectors drifting higher.

Levente Mady, a broker at MF Global Canada in Vancouver, said that the appeals court ruling came as a surprise to many, "so that's certainly why you're seeing that big reaction in the market".

With uncertainty already surrounding the BCE deal and its financing, "I don't know if it was actually going to happen anyway, but the fact that the court has surprised the participants certainly doesn't help any," Mady added.

The telecoms sector was slid 1.2 percent. Telus Corp , which had been in talks with BCE before the group led by the Ontario Teachers' Pension Plan emerged as the winner, was off 24 Canadian cents, or 0.5 percent, to C$47.68.

Also in the telecoms space, Manitoba Telecom Services rose after it said it had dissolved a consortium that was formed to bid in an upcoming wireless spectrum auction. MTS was up C$1.44, or 3.6 percent, to C$41.65.

Energy companies tumbled 1.1 percent as oil prices retreated after climbing to another record over $135 a barrel. Canadian Natural Resources was down C$1.83, or 1.8 percent, at C$102.10, and Imperial Oil gave up C$1.14, or 1.9 percent, to C$59.28.