XL signed a three-year deal with West Ham last February
West Ham have ended their sponsorship deal with collapsed travel firm XL Holidays and will play at West Brom on Saturday in an unbranded kit.
The Hammers have suspended all sales of replica shirts and hope to remove all branding from their Upton Park ground.
West Brom do not have a shirt sponsor, so Saturday's Premier League match will see both sides in plain strips.
The Hammers could face a £5m shortfall after XL went into administration on Friday, BBC Sport understands.
It is understood West Ham have only received £2.5m from a three-year deal with the Sussex-based travel company.
A £7.5m deal, worth £2.5m a year, was signed in February 2007 but only one year of the contract has been paid so far.
Hammers chairman Bjorgolfur Gudmundsson is also one of the guarantors of a 207 million Euros (£163m) bank loan given to XL.
A West Ham statement said: "In light of the circumstances surrounding the company, West Ham United have taken the decision to immediately terminate their relationship with XL Holidays.
"In view of this, the club have suspended all sales of replica shirts until further notice. This will also involve in due course the removal of XL Holidays branding from all West Ham United platforms."
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