TORONTO — Brian Tobin, the former Newfoundland and Labrador premier and federal cabinet minister, is leaving the Magna group less than six months after being named to senior posts at two of the auto parts giant's spinoff companies.

Magna announced late Friday that Tobin had resigned as chief executive of MI Developments Inc., a Magna real estate subsidiary, and from senior positions with MI's subsidiary Magna Entertainment Corp., North America's biggest horse racetrack operator.

The companies are all part of the Magna auto parts group controlled by Frank Stronach, one of Canada's best-known executives and a wealthy horse owner.

"I have great respect for the MI Developments team and for Frank Stronach," Tobin said in a release after stock markets closed Friday.

"My association with MI Developments since last August has been a good experience. I am leaving now to pursue other opportunities in the business world."

Tobin was replaced as CEO by chief financial officer John Simonetti, who has been with the Magna companies for a decade.

Besides quitting as CEO, Tobin also resigned as a director of MI Developments (TSX:MIM.A) and as the vice-chairman and a director of Magna Entertainment. Both companies are spinoffs of auto parts giant Magna International, and Magna founder Stronach is chairman of all three firms.

"Brian Tobin has been a great team leader and a great team player," Stronach said in a release. "The board of directors and I wish him well in his future business endeavours."

The companies did not say why Tobin is leaving the Magna group less than six months after being named CEO of MI Developments, a company that owns, develops, manages and leases industrial and commercial real estate in North America and Europe.

Earlier Friday, Stronach announced the appointment of former General Motors executive Mark Hogan as the new president of Magna International Inc., filling the post vacated by his daughter Belinda Stronach.

Belinda Stronach left the company earlier this year to go into federal politics, where she is now a Conservative member of Parliament.

Hogan has been with GM for three decades, most recently as group vice-president for advanced vehicle development.

During his political career, Tobin was federal minister of fisheries from 1993 to 1996, premier of Newfoundland from 1996 to 2000 and federal minister of industry from October 200 until January 2002.

Earlier this month, MI Developments reported a fall in second-quarter profits, hurt by losses at its Magna Entertainment unit.

In July, The Tobin-led company also made a $285.8-million offer in stock and cash for the 38 per cent of Magna Entertainment it doesn't already own.

MI had said it hoped the combined company can develop retail and gambling entertainment centres on land near existing tracks.