Construction group Carillion is understood to have invited bids from investors for part of its PFI equity portfolio.

It is believed that Secondary Market Infrastructure Fund, Henderson Private Capital and I2 have been asked to look at some of Carillion’s smaller investments. These are in areas such as education and secure accommodation, and are believed to be valued at upwards of £70m.

A source close to the bidding said that no one party would get the whole portfolio, which would be divided up among several companies.

An industry source added that the money raised from the sales would be used to help meet the cost of buying contractor Mowlem in February. Carillion spent £313m on this deal.

A spokesperson for Carillion declined to confirm the sale process, but said: “We keep an eye on the market, and if we believe that we can get greater value from selling investments we would consider it.”

Contractors often sell their PFI equity stakes after they have constructed the buildings, as at this stage the projects are considered low-risk and so sell at a premium.

Serco is also selling a chunk of its PFI portfolio, which is also valued at more than £70m. I2 is in place as preferred bidder, and financial close is expected in September.