TOKYO -- As Japanese and U.S. shares reach new highs fueled by the tech sector, strong earnings have allayed concerns about overheating, but the concentration of money in a handful of stocks has invited comparisons to the 1990s dot-com boom.
Some see 1990s dot-com-style bubble, but current stock prices supported by earnings

Though the Nikkei Stock Average topped 40,000 on March 4, only around 40% of its constituents ended the day higher. (Photo by Akira Kodaka)
TOKYO -- As Japanese and U.S. shares reach new highs fueled by the tech sector, strong earnings have allayed concerns about overheating, but the concentration of money in a handful of stocks has invited comparisons to the 1990s dot-com boom.