SECOND LARGEST STAKE

Yahoo Japan rival, Rakuten Inc, which recently agreed to become FC Barcelona's sponsor, still allows ivory sales on its site, but has stepped back from sales of whole tusks, a spokesman for the company said.

California-based Yahoo, which bans the sale of endangered animal products, says it can't force Yahoo Japan to change. Mayer has not publicly addressed the issue, though she has let it be known that she has raised concerns internally.

"Marissa has met up dozens of times with Yahoo Japan on this issue," said a source with knowledge of the meetings. "Sometimes it's engagement with board members and sometimes it's meetings with the CEOs," he added.

The Yahoo Japan spokesman confirmed that Mayer has met its CEO Manabu Miyasaka, but declined to give details of the talks.

Ron Bell, a counsel for Yahoo, issued a statement last year describing the relationship with Yahoo Japan as one of "passive ownership."

Aside from having it's brand above the door, Yahoo has a 35.6 percent stake in Yahoo Japan, second only to the 36.4 percent owned by the Softbank Group controlled by billionaire businessman Masayoshi Son. In Japan shareholders that own more than a third of a company's stock has the right to veto board decisions.

The US company declined to comment further when asked whether it would consider taking action.

Yahoo Japan declined to say how much it earned in commissions from online ivory sales. But EIA estimated it was $7 million in 2015, making just a tiny part of the $5.52 billion revenues Yahoo Japan reported for the 2015/16 financial year.