UPDATE 1-GM bondholders urged to accept new debt deal

* Bondholders see GM bankruptcy on Sunday or Monday

* 35 pct of GM bondholders seen already backing new deal

* US gov't would not be repaid until GM valued at $69 bln

By Kevin Krolicki

DETROIT, May 29 (Reuters) - Advisers to General Motors Corp
GM.N bondholders representing $27 billion in the automaker's
debt urged investors on Friday to support a debt swap negotiated
over the past week with the Obama administration.

Bondholders have until Saturday to register their support
for the terms of a deal that would give them up to 25 percent of
a reorganized GM. That offer is contingent on the U.S. Treasury
determining that enough investors have signed on in support.

Investors representing at least 35 percent of GM's bonds are
expected to support the sweetened offer from the U.S. Treasury,
which will be the automaker's largest shareholder and creditor.

In a conference call open to GM bondholders, advisers to an
ad hoc committee representing institutional investors urged
other bondholders to offer their support for the deal.

GM's bondholders have been advised by law firm Paul, Weiss,
Rifkind, Wharton & Garrison LLP and financial adviser Houlihan
Lokey Howard & Zukin Capital Inc.

Andrew Rosenberg, the legal adviser to the GM bondholder
committee, said investors should understand the automaker's
intent to file for bankruptcy on Sunday or Monday.

"GM, assuming its board approves, will file for bankruptcy
Sunday, Monday of next week," he said.

GM bondholders had been in intermittent talks with members
of the U.S. Treasury's autos task force overseeing GM's
restructuring since early in the year.

Earlier this week, bondholders rejected a proposal that
would have given them a 10 percent stake in the reorganized GM,
and a tender offer for new stock in the company was withdrawn.

In a sweetened deal, the U.S. Treasury and GM offered
bondholders warrants for another 15 percent stake under a
proposed deal that could be rescinded if too few bondholders
sign on to support it.

Rosenberg said the new deal terms had been negotiated in
"the last week."

Eric Siegert, who has been the financial adviser to the
bondholder committee, said the new deal represented a total
government investment in GM of nearly $60 billion.

For the government to be repaid in full, GM would have to
have an enterprise value of $69 billion based on its expected
72.5 percent stake in the company, Siegert said.

By the time GM reached that market value, bondholders would
have recovered $14 billion from their new equity, he said.

"That's a very, very unusual result that you have a junior
creditor ... where a company is in bankruptcy (and) where they
receive that much value before a senior creditor is paid in
full," Siegert said.

He added: "The federal government will not be paid in full
on its equity investment until the value of General Motors
reaches $69 billion."

Bondholder advisers said they would not disclose the names
of investors who supported the U.S. government's plan for GM,
which would include a quick sale of its best assets to a new
company funded by the U.S. Treasury.
(Reporting by Kevin Krolicki, David Bailey, Soyoung Kim,
Poornima Gupta and Walden Siew, editing by Matthew Lewis)