The corporate regulator has put Credit Suisse on notice after fining its equities arm $95,000 for failing to detect a false order placed on its automated trading system.
The trade was placed for a client on November 7, 2011, at an incorrect price - altering the market's official open and low prices for that day.
The Australian Securities and Investments Commission's disciplinary panel said it was the second time the group had been fined over failures with its automated trading system. The company has separately been sanctioned by the stock exchange' disciplinary tribunal on six other occasions since 2003 - on two because of automated trades.
The regulator said Credit Suisse had shown negligence over the misconduct, which had the potential to harm the reputation and integrity of the market.
"Credit Suisse did not self-report the breaches to ASIC and failed to inform both ASIC and the ASX in a timely manner," it said.
"Any future, repeat contraventions in similar or comparable matters will not be viewed favourably."
According to the Corporations Act, companies must have the technical resources in place to prevent any interference with the market. This includes ensuring their automated systems, which use algorithms to generate trades, correctly pick up changes to share prices.
Credit Suisse's false trade related to the sale of 2.9 million shares in failed global construction and engineering company Hastie Group. Credit Suisse's system failed to pick up changes to its share price earlier in the day when Hastie undertook a 10-to-1 consolidation of its shares.
As a result, the false order was placed at 47¢ lower than it should have been, at 51¢ - a 48 per cent difference.
ASIC noted that Credit Suisse had agreed not to contest the matter or dispute any material facts.
A Credit Suisse representative said: "Credit Suisse responded promptly to this incident and has put in place necessary processes to help prevent a reoccurrence."