Bord na Móna has signed heads of agreement to buy waste management company AES for a price understood to be in excess of €50 million.

It is understood that Bord na Móna will pay close to €50 million for Advanced Environmental Solutions (AES) and will assume about €6 million of debt.

The sale looks set to deliver a very healthy return for Bill McCabe's Oyster Technology Investments, which invested in AES early last year. Mr McCabe, the multimillionaire founder of e-learning company SmartForce, ended up with a stake of about 25 per cent in AES after a controversial rights issue in spring 2005.

That rights issue, which was underwritten by Oyster and Davycrest Nominees, raised €10 million as part of a refinancing of AES and restructuring of the company's debt. It provoked a shareholder storm because it carried out a pre-money valuation of €12 million, while earlier AES fundraisings had been carried out at valuations of €50 million.

Established in 1996 as Waste Recycling Ireland, AES raised millions over the years to fund a rapid and turbulent expansion. It raised nearly €22 million in one round in July 2002.

Other high-profile investors included Shane Reihill, founder of Trinity Venture Capital, and Frank Keane, who made his millions through operating the BMW franchise in Ireland.

Based in Naas, Co Kildare, AES had revenues of about €40 million last year. The latest filed accounts are for the year to June 2004, during which AES moved into operating profitability for the first time but reported a pretax loss of €6.47 million on turnover of just under €40 million.

The company has undergone extensive restructuring since the rights issue and is now understood to be safely in the black.