By Soyoung Kim and Clare Baldwin

NEW YORK (Reuters) - General Motors Co has
completed the paperwork for an initial public offering, and
timing of its filing with the U.S. securities regulators rests
with the board of the top U.S. automaker, sources familiar with
the process said Monday.

The initial prospectus, expected to be for $100 million, is
likely to be filed with the U.S. Securities and Exchange
Commission Tuesday, two people said, asking not to be named
because the preparations for the IPO are private.

GM updated its several-hundred page S-1 document to add a
management risk factor after Chief Executive Ed Whitacre said
Thursday he would step down and be succeeded by Dan Akerson
effective in September, the source said.

The surprise announcement last week was a factor delaying
GM's IPO filing by several days, several people close to the
process have said.

GM's IPO is expected to raise between $15 billion to $20
billion in one of the largest IPOs ever, the source said.

A group of 10 banks that committed to be the major group of
creditors in GM's $5 billion credit line will also serve as
underwriters for the stock offering, sources said.

The underwriting syndicate for GM's IPO will not be
finalized until closer to when the deal prices, but will
include minority firms, one source said.

The banks that have agreed to provide the credit line
include Bank of America Merrill Lynch, Barclays Plc
, Citigroup Inc, Credit Suisse ,
Deutsche Bank AG, Goldman Sachs, JPMorgan
Chase , Morgan Stanley, UBS AG
and Royal Bank of Canada , several sources said.

The source said that GM will add more banks to the credit
line while keeping the amount unchanged at $5 billion, reducing
banks' commitments from $500 million each.

The full syndicate for the credit line is expected to be
finalized by the end of September, one source said.

A quarterly filing by GM with the SEC Monday listed the
appointment of Akerson, 61, a veteran financial executive with
experience in the telecommunications industry, and the
appointment of former Microsoft executive Chris Liddell as
chief financial officer as risks for the company's operations.

"Within the past year we have substantially changed our
executive management team," GM said in the filing Monday in
language expected to be echoed in its IPO registration.

"We have elected a new chief executive officer ... and a
new chief financial officer ... both of whom have no outside
automotive industry experience."
(Reporting by Soyoung Kim and Clare Baldwin in New York, and
by Kevin Krolicki in Detroit; Editing by Phil Berlowitz and
Robert MacMillan)