SkillSoft PLC, an education software company that has agreed to be taken private, said a proxy advisory firm RiskMetrics Group is recommending that its clients vote in favor of the company's acquisition.

SkillSoft said in February it has agreed to be purchased by a private investor group, SSI Investments III Ltd., for about $1.1 billion.

SSI was formed by funds sponsored by Berkshire Partners LLC, Advent International Corp. and Bain Capital Partners LLC.