TOKYO -- Shares in Toshiba fell sharply on Wednesday after the Japanese company said CVC Capital Partners had in effect shelved its $20 billion buyout plan. CVC's plans have been complicated after the resignation of Toshiba's CEO, who clashed with activist investors. Formidable regulatory hurdles also loomed for any deal. The private equity group told Toshiba on Monday that it would "step aside" to await Toshiba's guidance as to whether privatization would fit with the Japanese company's strategic objectives, according to a Tuesday statement by Toshiba.