It was the first insider trading trial in New Zealand's legal history.
Formerly on Eroad's executive management team, Sansom was charged with insider trading by the Financial Markets Authority (FMA) after selling 15,000 Eroad shares for about $50,000 just days before its stock price plummeted.
The crash occurred after news went public of the company's poor performance as it attempted to break into the United States market.
The FMA accused Sansom, who has 30 years of business experience and had a lengthy career at Vodafone, of acting on a series of texts he exchanged with a former workmate,
The texts tipped him off about Eroad's US sales data in 2015.
The data showed Eroad, a publicly listed Kiwi company - which also operates in Australia and the US - was performing badly in the North American market, specifically Oregon.
Sansom sold his shares just two days after the received texts from Eroad's former insights and analytics manager Jeffrey Peter Honey.
Honey, who was hired at Eroad by Sansom after the pair grew friendly while working at Vodafone, has already been convicted and sentenced to six months' home detention for his part in the scandal.
Honey's September 22, 2015, message to Sansom read: "US sales not doing too well, time to sell up? Confidential obviously."
It also included a photo of an executive US sales summary.
"You're a bad boy, but thanks!" Sansom replied to Honey's text.
"Was going to sell down significantly anyway," Sansom said in a text a minute later.
On September 24, Sansom dumped his shares at a price of $3.41 each.
On November 19, 2015 the FMA received a referral from NZX (New Zealand's stock exchange) market surveillance about Sansom's trading and began its investigation into Sansom and Honey.
Hamish Sansom was a senior manager for Eroad, a transport and technology company. Photo / Greg Bowker
"[Sansom] is not some kind of criminal mastermind or the Wolf of Wall Street," he said, referencing infamous American stockmarket manipulator Jordan Belfort.
"His offending was unsophisticated and it was opportunistic rather than premeditated. He was well aware of the rules prohibiting insider trading ... he cheated."
Lowery said it was like knowing the lottery numbers in advance.
"It's not just stock traders who work in high-rise buildings and wear cuff links to work [who are affected by insider trading], but everyday New Zealanders ... particularly those who have KiwiSaver accounts," Lowery said.
"This case is as straightforward as the text messages we have seen. A well-placed company insider gave Mr Sansom a tip."
Sansom gave evidence in his own defence, denying the allegations, and said news of Eroad's poor sales were of no surprise.
He said he was concerned about the company's review of its financial performance.
"I was very concerned," he said, according to a Radio NZ report during the trial.
"I thought it was quite a poor performance if you looked at the numbers ... This was their most important year - this was the year when they had to prove themselves in Oregon."
He said while the New Zealand market was performing well the company was "walking on eggshells" about its North American expansion plans.
Jones also argued his client simply "knows the market", while Eroad had made business blunders.
"What you have is numbers that were known to Mr Sansom that were available through public announcements through Eroad," he said.
"The FMA want his head on a plate - they want a trophy. This was their first case under the new law," Jones said.
After today's verdict the FMA said in a statement it will "fully consider the outcome of this case".
"Insider trading, market manipulation and other unethical trading activity undermines market integrity and erodes investor confidence in New Zealand's financial markets," it said.
"The FMA will continue to investigate cases involving potential insider trading and based on the evidence obtained, refer these matters to the courts."
