MADRID, Dec 29 (Reuters) - Spanish energy group Acciona has made an offer for Grupo BTG Pactual SA's 39 percent stake in a Catalonia-based water company, a source close to the Spanish company said on Tuesday, as the Brazilian investment bank seeks to sell assets.
BTG Pactual is shedding non-bank investments and halting new loans, after the arrest of founder Andres Esteves in late November triggered client fund withdrawals and hampered its access to financing.
Acciona, which already owns 39 percent of Aigues Ter Llobregat (ATLL), has made a bid for BTG's 39 percent stake, the source said, confirming an earlier report in Expansion newspaper.
The source did not detail how much that stake would be worth, although according to Expansion the shares were valued at some 60 million euros ($66 million).
Acciona declined comment.
The rest of ATLL is owned by two Catalan family shareholders.
Esteves was detained on suspicion of obstructing an investigation into corruption at Brazilian state-controlled oil producer Petroleo Brasileiro SA, or Petrobras. He has since been released.
A group of companies led by Acciona and including BTG won a 50-year water distribution contract for the ATLL concession in 2012, but the deal was contested by a rival bidder and the dispute is still going through the courts.
Acciona said in a filing to Spain's stock market regulator on Monday that if its deal with ATLL was revoked, it should be entitled to at least around 300 million euros in compensation. ($1 = 0.9116 euros) (Reporting by Jose Elias Rodriguez; Writing by Sarah White; Editing by Carlos Ruano and David Holmes)