Edward Brogan was Japan's highest-profile hedge fund manager until he suddenly dropped out of view this month. Dubbed the "King of Tokyo" by traders, the 53-year-old American seemed to have it all: wealth, professional acclaim and status as a patron of contemporary art.

In his best year, Brogan had managed over one billion dollars in his flagship Whitney Japan Fund, although much of that has been withdrawn.

Now Brogan is at the center of a probe of insider trading. His Tokyo-based firm Japan Advisory has been closed since regulators imposed a fine and revoked its license at the end of June.

The order came after Japan's securities watchdog determined Japan Advisory had shorted shares in Nippon Sheet Glass in August 2010 on the basis of leaked information that the glassmaker was planning an additional share offering that would have diluted its value per share.

It was one of five insider trading cases unearthed so far by authorities after a grinding two-year investigation into allegations of widespread insider trading ahead of public share offerings in Japan.