A US court has reversed an $11 million (£6.9 million) judgement against Spamhaus, a British anti-spam firm alleged to have caused extensive financial losses by blacklisting American marketing company e360.

Spamhaus will now only need to pay a nominal three dollars after the US Court of Appeals ruled that e360’s calculations of lost business were “fundamentally unsound”.

e360’s damages claim had at one point hit $135 million, according to the Out-Law blog from law firm Pinsent Masons, though a judgement was reached in 2006 ordering Spamhaus to pay $11 million. This was reduced a year later to $27,000 on the weakness of the evidence.

In the latest judgement, the court said e360 had been making calculations based on lost profits rather than lost revenues.

The judge, Charles Kocoras, wrote that rather than e360 providing “a reasonable estimate of the harm it suffered from Spamhaus’s conduct", it had “engaged in a pattern of delay” that had hindered procedure.

e360’s lone witness had “painted a wildly unrealistic picture” of the company’s losses, he added.