Koyasan Shingon Buddhism, the owner of a cluster of World Heritage Site temples founded in the ninth century, reported losses equal to about a quarter of its assets after bets on the Australian dollar and structured bonds soured.

The group had unregistered losses of ¥1.53 billion on financial assets of ¥5.79 billion for the year ended March 31, according to an April 23 report commissioned by the organization, based in Wakayama Prefecture. The head of the organization, Kosho Shono, resigned Wednesday to take responsibility.

Koyasan Shingon, whose flagship Kongobu-ji Temple on Mount Koya is listed as a National Treasure of Japan, started investing in 2002 in an Australian dollar fund through Nomura Securities Co., using money from member temples and followers. The association later expanded its portfolio to products including Nikkei index-linked debt, according to the report.

Holding the association’s fund managers responsible for the losses “wasn’t appropriate,” because it would have been difficult to predict the 2008 collapse of Lehman Brothers Holdings Inc., the report said.

The report was commissioned in February after the organization’s governing council asked for more transparency about its investments.

“It was a difficult period of investing that led to attempts at higher returns. Such movements were seen everywhere,” said Hiroyuki Nakai, chief strategist at Tokai Tokyo Research Center.