General Motors chief quits ahead of shares offering

General Motors chief executive Ed Whitacre has resigned as the car giant prepares a shares offering to pay back its bailout from the US taxpayer.

Dan Akerson, a veteran private equity investor little known in the motor industry, will replace Whitacre next month.

Akerson, 61, was appointed by the Obama administration as one of the directors meant to safeguard the government's $50 billion financing to restructure GM.

Whitacre's departure was expected but the timing of his announcement even surprised insiders, a day before the firm was expected to file the paperwork for a landmark stock offering just over a year after its emergence from bankruptcy.

Whitacre, 68, had said repeatedly he would be an interim leader and continued to commute from his home in Texas during his stint in charge of the Detroit-based company,.

Akerson, also a former CEO at Nextel, becomes GM's fourth chief executive in just a year and a half, underscoring the challenge the firm faces in the early stages of its turnaround.

"We still have important work ahead of us, but I am confident that we are building the foundation for GM's long-term success," Akerson said in a hastily-arranged appearance at the end of a conference call to discuss the firm's second-quarter earnings.

The question of Whitacre's tenure was raised at a GM board meeting two weeks ago when former director Kent Kresa, 72, resigned, according to a source. Kresa had been on the GM board since October 2003 and had reached the mandatory retirement age.

Whitacre then made it clear he wanted to step down at the end of the year, about a month after GM is expected to launch an IPO expected to be one of the largest ever.

Board members asked Whitacre if he would consider committing to a longer term, but when he would not they turned to Akerson, who had been a candidate for chief executive after the departure last year of Fritz Henderson, according to the source.

The US Treasury said GM's board made the decision on the CEO change. Officials who asked not to be named said there had not been any tension between Whitacre and the Obama administration on the direction of the company.

Even so, the sudden nature of the executive change could have repercussions for the perception of GM and its IPO. Most immediately it could delay GM's filing, planned as early as today, until next week, sources said.

"The instability certainly is a shock to insiders; it's stunning to outsiders and you don't usually have that happen," said Jeffrey Sonnenfeld, of the Yale School of Management.

South Beach Capital Markets Advisory Corp president Bruce Foerster said the shake-up at the top of GM risked having investors add a new risk premium to its IPO.

"You needed the sun, moon and stars all aligned and now they're out of whack again," he said.