The Nikkei stock average fell below the 16,000 line Tuesday as worried investors sold off Internet stocks amid the dust kicked up by prosecutors' search of Livedoor Co. over suspected securities law violations.
The Nikkei lost 462.08 points in its biggest single-day loss since May 2004 to close at 15,805.95, down 2.8 percent from the previous day.
Despite the news, the downside is likely to be limited by strong buying by foreign investors, market participants said.