The US Securities and Exchange Commission (SEC) has reportedly subpoenaed Apple chief executive Steve Jobs in its case concerning alleged back-dating of stock options.

News agency Bloomberg cited sources "familiar with the matter" as saying that Jobs had been called to give a deposition in the SEC's suit against Nancy Heinen, Apple's former general counsel.

The Bloomberg report stressed that Jobs is not the target of an investigation, and that the subpoena is related only to the case against Heinen.

An SEC spokesperson had no comment on the reports. Apple did not return a request for comment.

The SEC filed suit against Heinen in April, alleging that she had knowingly back-dated stock options awarded to Jobs and other Apple executives in 2001.

The practice allows employees to maximise their earnings. Although common, back-dating has come under fire from regulators.

Former Apple chief financial officer Fred Anderson was also named in the April filing, but immediately agreed to pay a $3.65m settlement.

The SEC has cleared Apple of any wrongdoing and vowed not to charge the company itself in the case. However, an SEC spokesperson told vnunet.com in April that the protection will not extend to individuals within the company.

A 2006 internal investigation by Apple cleared all current employees, including Jobs, of any wrongdoing.