News broke that Swiss base Finance Brokers, Alpari, who became the Hammers' shirt sponsor in February 2013 in a deal understood to be worth around £3m-a-year, entered insolvency proceedings on Saturday morning after taking huge losses as a result of the Swiss National Bank's move to decouple from the Euro.
"The recent move has resulted in exceptional volatility and extreme lack of liquidity," an Alpari statement read.
"This has resulted in the majority of clients sustaining losses which has exceeded their account equity."
Alpari were committed to being West Ham's principal shirt sponsor for at least the next 18 months after signing a renewal of its sponsorship in 2013.
According to the Star on Sunday the west stand of Upton Park is also named after the broker, whose logo and name from the club's shirt and stand could now be removed.
West Ham have previously faced troubles with its shirt sponsors.
In 2008, the club's principal sponsors, XL, went out of business and were forced to close a £4m-a-year sponsorship deal.
The Hammers, in 1997, were left without a sponsor for the entire season after a proposed deal with a South African airline company fell through.