After a number of accounting errors, including a restating of Q1 results, General Motors has announced plans to restructure its corporate controller's office as current controller Paul Schmidt nears retirement later this year.

GM said that, following Schmidt's retirement, it would combine the positions of controller and chief accounting officer and has begun an external search for a candidate. Schmidt will continue in his current position until a successor is named.

GM also announced that its current chief accounting officer, Peter Bible, will resign on 1 June, but will remain for a time in a consulting role.

GM also said it has retained an outside financial advisory firm, AlixPartners, to assist the corporation with a broad range of accounting, financial reporting and related matters.

The firm will provide personnel to support the corporation during the transition to a new controller and chief accounting officer, including assisting with assessments of the corporation's internal, financial reporting and disclosure controls and implementing steps to improve them.

"One of our key objectives in finance is to minimise risk," said GM CFO Fritz Henderson.

"To that end, we are moving quickly to make sure that we have a robust level of internal controls and systems in place - and AlixPartners has tremendous expertise to support this initiative."

"The resignation of GM's chief accountant is a sign all is not well," Sean Egan, managing director of Egan-Jones Ratings, told the Reuters news agency.

Reuters added that the choice of AlixPartners has worried some analysts because the firm has helped several companies reorganise through 'Chapter 11', including WorldCom - the largest corporate bankruptcy in US history.

GM shares fell on the news and HSBC analyst John Kollar told Reuters: "The reaction in the marketplace to the news today had really little to do with the change in personnel at General Motors. It was the hiring of AlixPartners as a financial advisor that has the bond market a bit spooked at this point, because Alix is a distressed company financial advisor."

GM reportedly said it was not hiring the firm to help with its restructuring.

"We're hiring them for their expertise in the accounting transition," GM spokesman Jerry Dubrowski told Reuters. "We're not hiring them for help in the turnaround effort for our North American operations."

Reuters noted that GM, which earlier this year restated earnings going back several years, is also under investigation by the US Securities and Exchange Commission for transactions involving supplier credits and precious metals.

"They are making these changes because they need to," Burnham Securities analyst Dave Healy told the news agency of the restructuring in accounting ranks. "There is this perception out there that GM accounting is corrupt. It is not, but there is the image."

GM accountants turn Q1 loss into profit