The initial purchase price is £460 million, approximately $610 million, in cash.

The deal is expected to close by the end of the year. The pair agreed to a multi-year earnout of up to £300 million, approximately $400 million, subject to Onnec meeting certain growth targets.

After closing, Onnec will operate as part of CBRE's Critical Infrastructure Services line of business. Goldman Sachs International is acting as financial advisor to Onnec.