U.K. environmental utility infrastructure company Pennon Group PLC hired Morgan Stanley and Barclays as it explores a £4 billion sale of its Viridor Ltd. unit, The Daily Telegraph (London) reported, citing City of London sources.

The move reportedly follows a bid from private equity giant KKR & Co. Inc. to buy out the bin collection and incinerator business in early 2019. Pennon first said in September 2019 that it was evaluating options for Viridor, the publication noted.

Advisers reportedly have informally reached out to prospective buyers to gauge interest and are working to formally launch an auction.

Neither Pennon nor KKR commented on the matter, according to the publication.