New York--DoubleClick Inc. subsidiary DoubleClick Japan completed an IPO. Tokyo-based DoubleClick Japan raised $27 million in its offering, reducing DoubleClick Inc.'s stake in it to 38.2%, from 43.2%. Nikko Salomon Smith Barney Ltd. led the IPO. It comes as Japan's online advertising and direct marketing sectors are expanding markedly. Online advertising in Japan increased 144% last year, to $485 million.