Intrade, the popular online betting site, abruptly shut down Sunday citing "financial irregularities" that the firm said it will investigate.
The Dublin-based website, which has faced previous scrutiny over its business model, allowed consumers to place bets on world events such as elections and the selection of a new pope.
In a statement posted to its website Sunday, Intrade said it would immediately halt all trades, settle all open positions and cease all banking transactions for customers.
"During the upcoming weeks, we will investigate these circumstances further and determine the necessary course of action," the company said.
Intrade members will not receive any payments until the investigation is complete, Intrade said.
Late last year, the U.S. Commodity Futures Trading Commission filed a civil complaint against Intrade in federal court. The action effectively blocked U.S. residents from using the site.