A regional bank in Japan is sitting on sixfold gains from early bets on stocks including Nintendo, creating a portfolio that’s now worth more than the lender itself.

Kyoto Financial Group, named after the ancient city of temples where it’s based, has equity holdings worth almost $6 billion (¥903 billion), thanks to investments made decades ago in startups from the same area of Japan.

While equity holdings like these have been criticized by investors lately as inefficient uses of capital, Kyoto Financial President Nobuhiro Doi said he doesn’t think selling them now is a good idea. He sees no alternative investments that can generate such strong returns.