A re-run for New Zealand's first insider-trading trial will be held over the next two weeks.

Hamish Marc Sansom worked as a senior manager for Eroad, a transport and technology company.

He was charged with insider trading under the Financial Markets Conduct Act.

His was the first criminal trial on such a charge in New Zealand's legal history, however, the first trial ended in a hung jury in March.

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Today, the jury to hear his retrial was empanelled before opening addresses will be delivered tomorrow.

The Financial Markets Authority's (FMA) prosecution of Sansom was over evidence from a series of texts he exchanged with a former workmate after a tip-off about Eroad's United States sales data in 2015.

The confidential data showed Eroad, a publicly listed Kiwi company - which also operates in Australia and the US - was performing badly as it attempted to break-in to the North American market.

Sansom sold 15,000 of his shares in the company just two days after he received texts from Eroad's former insights and analytics manager Jeffrey Peter Honey.

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 sales summary.

On September 24, 2015, when Sansom sold the 15,000 Eroad shares he did so at a price of $3.41 each.

Four days passed before news of Eroad's US sales setback went public, crashing its stock price.

The announcement resulted in the biggest daily and weekly fall in Eroad's trading history, since its initial public offering in August 2014.

By October 2, 2015, its shares were trading at $2.60 each - dropping by 21 per cent.

On November 19, 2015 the FMA received a referral from NZX market surveillance about Sansom's trading and began its investigation.