West Ham owners David Sullivan and David Gold were accosted by angry fans following the Hammers' 2-0 FA Cup defeat to Wigan on Saturday.
According to Sky Sports, the owners came under fire from the club's supporters over their loaning of Portugal international Joao Mario from Inter last week - not that they were against the deal, but upset at him being the only incoming player all month.
Mario joined the Irons for the remainder of the season and will earn £100,000-a-week, with the club also parting with £2m to secure the loan. And while senior officials at the club claim to understand the fans' frustrations, they admit that it has been difficult to get deals over the line during the current window.
They are still willing to bring in new faces, though, yet aren't hopeful of signing any other players before the deadline.
Meanwhile, Hammers boss David Moyes is hoping that Mario will add a bit of quality and creativity to the team.
“I was at the Euro 2016 final when Portugal played France, so I had an opportunity to watch Joao there,” the manager told the club's official website.
“He can play in a number of roles. There’s a little bit of Manuel Lanzini about his play. He could play off the left or right and even as a No10 if needed.
“I hope he will be a player who will create and score a few goals for us. Even before Manu’s injury we were looking to add some creativity but now the need for that type of player is even more acute.
“At the start of the window the move didn’t look like it would happen but as the days have gone on it became more likely.”