A New Zealand-based stock picker will have to pay at least $275,000 after defaming a prominent Australian mining investor via social media, a court has ruled.
Alan Francis Davison, the man behind the Stock Swami Twitter account, defamed Tolga Kumova through multiple social media posts alleging he was involved in a syndicate engaged in "pump and dump" schemes to inflate the value of stocks they owned, Justice Michael Lee told the Federal Court on Monday.
Justice Lee said Mr Davison was not simply "tilting at windmills" with the allegation.
"But the very seriousness of market manipulation in any form means that a public accusation of pumping and dumping or insider trading must be approached responsibly and with a degree of circumspection," he said.
The bulk of Mr Davison's various defences did not stack up, the judge said.
"It should have been obvious from the start that a number of these defences were untenable on the facts," he said.
The stocks did not appear susceptible to a pump and dump scheme and there was no evidence any "dump" took place outside normal trading activity or that Mr Kumova was involved in a criminal syndicate conducting such a scheme.
Justice Lee accepted Mr Kumova's claim his social media posts about specific stocks he had invested in growing in value were prideful boasts, not designed to encourage others to invest.
"(It) was, at least in large part, an exercise in swaggering braggadocio directed to telling the world about his skills, his wealth and his perceived success.
"Behaviour of this kind is not unique in the world of social media," the judge said.
Mr Kumova's own conduct in some instances was troubling but the allegations he was involved in a criminal syndicate and manipulated markets were not substantially proven, the judge said.
Mr Davison had pursued a campaign against Mr Kumova through his own Twitter account and complaints to regulators, and an apology he offered was not accepted as genuine by the judge.
Documents were also destroyed or withheld from discovery by Mr Davison, which played a role in the judge awarding aggravated damages.
Justice Lee also criticised Mr Davison and his legal team Xenophon Davis over public commentary made on the ongoing case.
"A solicitor mocking a witness on social media while they are under cross-examination and because of the evidence they have given should not occur," Justice Lee said.
Mr Kumova has been awarded $275,000 in damages with a hearing in February to determine payment of legal costs and restrictions on material being republished.
The decision is a vindicating end to "years of harassment I have suffered at the hands of an online troll on Twitter," Mr Kumova said in a statement.
"This court action was about defending my personal and professional reputation from unwarranted attack, and for those many people who have suffered abuse on social media from anonymous trolls," he said.
Mr Davison's lawyer Mark Davis said the judgment is being reviewed and a response will be made in due course.