General Motors Corp. failed to get 90 percent of its bondholders to swap their claims for stock, pushing the largest U.S. automaker closer to bankruptcy, Bloomberg reported this morning.

The principal amount of notes tendered was “substantially less than the amount required by GM” and, as a result, “the exchange offers will not be consummated,” the company said today in a statement. GM faces a government-imposed June 1 deadline to restructure or file for bankruptcy.

The automaker, propped up by $19.4 billion in emergency U.S. loans, will file for bankruptcy protection after failing to get 90 percent of bondholders to swap their debt, CEO Fritz Henderson said. The exchange offer was opposed by both institutional and individual investors, who said they’ve been treated worse than a union retiree medical fund.

“It’s no surprise at all that a deal that was as unattractive as this one would be soundly rejected,” said Pete Hastings, a fixed-income analyst at Morgan Keegan & Co. in Memphis, Tenn. Bankruptcy is “imminent,” said Hastings, who urged his clients to refuse the exchange offer.

The decision on a bankruptcy is “up to the GM board to decide, and that meeting is later in the week,” said Julie Gibson, a company spokeswoman. She declined to be more specific on the timing of the meeting.

Bondholders were offered 225 shares in a newly created entity for each $1,000 in principal before a 1-for-100 reverse split of the stock. That equated to a 10 percent stake in the reorganized company for their $27 billion of debt.

The automaker also said it canceled meetings with holders of non-dollar-denominated notes that were scheduled to take place today.