* Filings show Stronach stake at 1 mln shares
* Equal to 0.4 pct stake in, according to data
* Sales speeded up in May and June
* Stronach stepped down aschairman in May (In U.S. dollars unless noted)
VANCOUVER, June 21 (Reuters) - Magna International Inc founder Frank Stronach has been slowly but steadily reducing his stake in the auto parts company he founded, insider regulatory filings show.
Data shows Stronach has sold nearly 17 million common shares in Magna since early December, leaving him with 1 million shares as of June 17, according to filings made to Canada's System for Electronic Disclosure of Insiders, or SEDI.
That leaves Stronach with a stake of about 0.4 percent in Magna, based on outstanding common shares of 242 million, according to Thomson Reuters data.
After a slower start to the year, sales picked up steadily in May and June. Shares were sold at prices between $45 and $52.53 over the two months.
Magna shares closed up $1.47 at $49.65 on the New York Stock Exchange on Tuesday. In Toronto, they finished 2 percent firmer at C$48.23.
Stronach stepped down last month as chairman of the auto parts company that he started as a one-man tool and die shop in a Toronto garage in 1957. It now has 96,000 employees and expects revenues of around $27 billion this year.
The company implemented a controversial plan last year to buy out Stronach for $1 billion in cash, common stock and other benefits in return for his controlling share block.
($1=$0.97 Canadian) (Reporting by Nicole Mordant; editing by Rob Wilson)