Billionaire and activist investor Carl Icahn said that he had raised his stake in Nuance Communications Inc. The latter is a speech recognition software manufacturer. Icahn increased his stake to 16.9%. He also said that he might discuss the possibility of adding his nominees to the firm.

Earlier this month, Icahn reported a stake of 16.03% at the speech recognition software maker.

On Thursday, Nuance shares increased by 2% in extended trading after it closed at USD18.31 on the Nasdaq.

After Icahn's announcement of his owned shares at Nuance, the company adopted a stockholder rights plan. The plan stated reducing chances of any investor gaining control through coercive tactics without paying appropriate control fees. The provisions would take effect after a person or group purchases 20% or more of Nuance's shares in deals that have not been approved by its board.

Carl Icahn is known to in taking large positions in companies and push for management change. The billionaire investor said that he had taken 9.27% stake in Nuance.