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.