The Telegraph claim United have told Louis van Gaal they will back him with £100million to try and lure the former Tottenham man back to the Premier League this summer.
Chelsea have also been linked with Bale, who has been subject to criticism from fans and press this season.
Reports in Spain claim Wayne Rooney has been offered to Barcelona
Spanish newspaper Sport claim United trio Wayne Rooney, Juan Mata and Ander Herrera have all been offered to Barcelona - along with Manchester City playmaker David Silva.
That is despite Barca being under a transfer embargo that prevents them signing any players until January.
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United and Chelsea both want the right-back who will enter the final year of his contract this summer.
"We're still speaking with Clyney and his agent, but of course we have to know in 10 days," Koeman said.
"The club is doing an offer the maximum what we can do and then we expect the player's answer."