Two Norwegian day traders have been handed suspended prison sentences for market manipulation after outwitting the automated trading system of a big US broker.
The two men worked out how the computerized system would react to certain trading patterns – allowing them to influence the price of low-volume stocks.
The case, involving Timber Hill, a unit of US-based Interactive Brokers, comes amid growing scrutiny of automated trading systems after the so-called “flash crash” in May, when a single algorithm triggered a plunge in US stocks.
Svend Egil Larsen and Peder Veiby had won admiration from many Norwegians ahead of the court case for their apparent victory for man over machine.
Prosecutors said Mr Larsen and Mr Veiby “gave false and misleading signals about supply, demand and prices” by manipulating several Norwegian stocks through Timber Hill’s online trading platform.
Anders Brosveet, lawyer for Mr Veiby, acknowledged that his client had learnt how Timber Hill’s trading algorithm would behave in response to certain trades but denied this amounted to market manipulation.
“They had an idea of how the computer would change the prices but that does not make them responsible for what the computer did,” he told the Financial Times. Both men have vowed to appeal against their convictions.
Messages posted on Norwegian internet forums on Wednesday indicated widespread sympathy for the defendants. “It is the trading robots that should be brought to justice when it is them that cause so much wild volatility in the markets,” said one post.
Mr Veiby, who made the most trades, was sentenced to 120 days in prison, suspended for two years, and fined NKr165,000 ($28,500). Mr Larsen received a 90-day suspended sentence and a fine of NKr105,000.
The fines were about equal to the profits made by each man from the illegal trades.
Christian Stenberg, the Norwegian police attorney responsible for the case, said any admiration for the men was misplaced. “This is a new kind of manipulation but it is still at the expense of other investors in the market,” he said.
Interactive Brokers declined to comment.
Irregular trading patterns were first spotted by the Oslo stock exchange and referred to Norway’s financial regulator.