April 3 (Bloomberg) -- An unidentified investor placed a sell order for 56.5 million shares in Japanese brokerage Nikko Cordial Corp., which is the subject of a contested $13.4 billion takeover offer from Citigroup Inc.

Ten different entities entered orders to sell Nikko shares at 1,900 yen ($16) on the Tokyo exchange, according to Instinet Japan Ltd. The size of the stake matches the holding of Orbis Investment Management Ltd., which yesterday spurned Citigroup's 1,700-yen bid and said it would sell its shares in the market at 1,900 yen.

Bermuda-based Orbis and other overseas investors including Harris Associates LP are pushing Citigroup to offer more for Nikko, Japan's third-largest brokerage. Harris Associates sold part of its stake after Citigroup said the bid, which was raised from 1,350 yen a share on March 13, won't be boosted further.

``Orbis is sending a message to other shareholders that they shouldn't accept the offer and that they should wait for the chance that Citigroup may raise it again,'' said Fumiyuki Nakanishi, a Tokyo-based equity strategist at Sumitomo Mitsui Financial Group Inc.

To contact the reporters on this story: Takahiko Hyuga in Tokyo at thyuga@bloomberg.net; Joseph N. DiStefano in New York at jdistef@bloomberg.net

Last Updated: April 2, 2007 22:39 EDT