Yusaku Maezawa bought an 8% stake in United Arrows for 3.5 billion yen ($32.78 million) and a 6% stake in Adastria, another retail group, for 3.9 billion yen, according to the filings.

The moves were for investment purposes with friendly intentions, the filings said, while adding that he may "make proposals or offer advice to management if needed".

Maezawa, who has signed up for a trip around the moon with Elon Musk's SpaceX and is known for hosting cash giveaways on Twitter, stepped down as CEO of Zozo last year when he sold it to SoftBank Group Corp.

He said he earned around 150 billion yen from the sale, even after retaining an 18% stake in Zozo.

Zozo's online mall started out by selling brands with an edge, but now carries a wide range of names and is the most popular shopping site for mid- to high-end fashion.

(Reporting by Ritsuko Ando; Editing by Muralikumar Anantharaman)