Sanrio Co. shares tumbled the most since May 2014 after the brand owner of Hello Kitty said holders including its president will sell shares in a secondary offering.

Shares of the Tokyo-based company sank as much as 17% in early Tokyo trade, on volume more than triple its three-month average, according to data compiled by Bloomberg. President Tomokuni Tsuji and MUFG Bank Ltd. will sell about 25.9 million shares, with price to be decided as soon as Dec. 10, according to a filing to Japan's Finance Ministry.