Updated from 1:31 p.m. EDT

Boeing

(BA) - Get Report

shares were flat Friday after the airplane maker acknowledged joining the list of companies under government scrutiny for pension accounting.

The Chicago-based company said it received a request for information from the

Securities and Exchange Commission

about how it accounts for pensions and other retirement benefits.

In a statement, Boeing said it's cooperating with the inquiry. Earlier this week,

Ford Motor

(F) - Get Report

,

General Motors

(GM) - Get Report

,

Delphi Corp.

(DPH)

and

Northwest Airlines

(NWAC)

acknowledged receiving similar requests from the SEC.

"Boeing believes that its accounting policies and practices are in accordance with the highest standards and are accurate and complete," Boeing said in a statement late Thursday. "However, due to the early stage of this matter, the company is unable to predict what conclusions, if any, the SEC will reach."

Boeing shares added 6 cents, or 0.1%, to $49.62.

Boeing's announcement comes at a time when its CEO, Harry Stonecipher, is trying to repair the company's reputation in the wake of a high-profile ethics scandal. Darleen Druyun, a former Defense Department acquisition official, admitted she favored Boeing while negotiating a $250,000-a-year Boeing job for herself as well as employment for family members. Druyun received a nine-month prison sentence earlier this month, after her April guilty plea to a federal conspiracy charge. Last November, Boeing fired her and Michael Sears, the company's former CFO, for unethical behavior; the scandal also forced the resignation of then-CEO Phil Condit in December.

Druyun's confessions prompted Pentagon inquiries into Air Force procurement and spurred lawmakers to bar Boeing from plans to lease the government aerial tanker jets for $23.5 billion, although Congress left the door open for Boeing to bid on future government tanker purchases.

Earlier this month, Boeing rival

Lockheed Martin

(LMT) - Get Report

protested other Air Force contracts that may have involved Druyun, including a $4 billion contract to upgrade C-130 cargo planes.