The group had said its security systems had been breached with “unauthorised access gained via a single and isolated user account” but insisted the hack would not affect its ability to do business.
“As soon as it was discovered, Clarksons took immediate steps to respond to and manage the incident,” it said.
Clarksons had been bracing for a tranche of private data to be released by the person behind the hack.
Its research operation collects and analyses data on merchant shipping and offshore markets.
In August, Clarksons reported a 6% rise in first half revenue to £156.8mln, while profit before tax increased 25%to £21.9mln. The company said while overall freight levels were low, it had seen “very early signs of recovery” in some of the major shipping markets.
“As we see signs of a rebalancing across some of the shipping markets, we are optimistic in our ability to capitalise on the upturn in the markets when it occurs, while maintaining the strength of the underlying business,” it said.
“Nevertheless, in the short-term, low activity in the new building market and a predominance of spot over longer-term period business continues to limit forward visibility of revenues.”
The company reports its full year results on March 12.