Omers Private Equity is weighing options for ERM Group Inc., including a potential sale that could value the sustainability consultancy at as much as US$2.5 billion, people familiar with the matter said.

The unit of Canada’s Ontario Municipal Employees Retirement System is speaking with potential advisers about strategic alternatives for the business, the people said, asking not to be identified discussing confidential information.

Omers could start a sale process early next year, the people said. It acquired ERM for US$1.7 billion including debt in 2015 from Charterhouse Capital Partners. Another Canadian fund, Alberta Investment Management Corp., also participated in the acquisition.

Talks are ongoing, and no final decisions have been made, the people said. Representatives for Omers and Aimco declined to comment, while ERM didn’t immediately respond to queries.

ERM advises companies in industries from mining to manufacturing on the environmental and social impact of their operations. The potential sale of ERM comes at a time when the business world is paying ever-closer attention to sustainability issues amid pressure from investors.

Private equity firms are looking to take advantage of demand for specialist advice. Carlyle Group Inc. is reviving plans for the sale of the U.K.’s PA Consulting Group in a deal that could fetch more than 1 billion pounds (US$1.3 billion), Bloomberg News reported in September.

ERM employs more than 5,500 people in over 40 countries, according to its website. The company’s gross revenue increased 9 per cent last year to US$983 million. Its earnings before interest, taxes and amortization rose 25 per cent to US$121 million.