The statement followed a drop in the value of the Dow Jones Industrial Average index of nine per cent, the largest daily decline in its history.
Fears over the escalating debt problems in Greece are thought to have triggered the fall, which saw the index close at approximately 3.2 per cent down.
According to reports, rumours also circulated implying that a Citigroup trader may have made the âerroneous tradeâ which contributed to the fall.
In the statement, the CME Group said: âWhile our policy is not to comment on individual participation in our markets, in light of volatile market conditions, CME Group confirmed that activity by Citigroup Global Markets Inc. in CME Group stock index futures markets does not appear to be irregular or unusual in light of market activity today."
A spokesman for Citigroup said that there was no evidence to suggest that the bank had been involved in any irregular transactions.
âWe, along with the rest of the financial industry, are investigating to find the source of todayâs market volatility,â he explained.
By Jim Ottewill