Life insurer Prudential Assurance Company Singapore is suing former agency leader Peter Tan Shou Yi for up to $2.5 billion after 244 of its agents jumped ship to join him at rival firm Aviva, leaving 70,000 policies without agents as a result.

The insurer said Mr Tan, 54, had offered loyalty bonuses to those who left with him and had agents sign non-disclosure agreements while he planned the move.

In a High Court trial that started yesterday, Prudential is claiming "significant and long-lasting loss" over the alleged poaching by Mr Tan. It estimates its losses in profits to be around $300 million if the agents had stayed on to 2025; and if they stayed in perpetuity, the losses would amount to $2.5 billion.

The time frames were taken in view of a Pegasus Agreement that Mr Tan signed with Prudential just a year before the mass defection. It contained projections of his and his agents' performance for at least 10 years, suggesting Prudential's losses were unlikely to be limited to a short period of time, the court heard.

Mr Tan joined Prudential as an agent in 1997, rising through the ranks to become a group agency manager in 2006.

He built and led the Peter Tan Organisation (PTO) until 2016, when he left Prudential.

At its height, the sales force he recruited and trained was the largest, most productive sales force in Prudential, numbering some 500 agents and agency leaders. But nearly 200 of these resigned over three days in June 2016, with more following later.

Prudential accused Mr Tan of "surreptitiously" orchestrating the mass defection to Aviva and its subsidiary financial advisory firm from May to July 2016.

It also said Aviva "furnished a war chest of at least $100 million to $150 million" to recruit from PTO, and expected to get a base of 250 agents.

PTO was the top producer at Prudential before the exodus, and generated $141 million in new business profits as well as a total annual premium equivalent of $192 million from 2011 to 2015.

If Mr Tan, who earned $9.7 million in the year before he defected, could get another 100 agents on board, he would receive an annual bonus as well, Prudential's lawyers from Rajah & Tann, led by Mr K. Muralidharan Pillai, said in their opening statement yesterday.

"The defendants would like the court to believe that this mass migration... was the result of coincidence, normal attrition and possibly even loyalty to (Mr Tan)," lawyer Paul Tan of Rajah & Tann told the court.

"One swallow may not make a summer, but 244 agents make it an unlawful, illegitimate en bloc solicitation of Prudential's agents."

Prudential's lawyers also said in their submissions to the court that Mr Tan compelled agents to sign non-disclosure agreements, travel to Guangzhou from May 26 to 29, 2016, to discuss the defection, and warned them not to inform Prudential of the move. They said he held at least 12 meetings with agents.

Mr Tan, represented by law-yers from TSMP Law Corporation led by Senior Counsel Thio Shen Yi, contends that the regulatory and commercial landscape made Aviva's model more attractive and that it was decisive in causing the defection.

Mr Tan also argues that regardless of his acts, his departure from Prudential would have caused several other senior agency leaders to leave with some agents - which the insurer contests.

Prudential argues Mr Tan had to persuade the agents to move.

It said as well that Mr Tan breached his fiduciary duties, which could arise from the fact that he had influence over Prudential's agents and could thus directly affect the company's economic interests.

The insurer is also suing PTO Management and Consultancy (PTOMC), of which Mr Tan is the sole shareholder and director. It claims PTOMC had assisted Mr Tan's breaches of fiduciary duties.

Mr Tan, through his lawyers, is counter-claiming that Prudential terminated his service in an invalid manner, causing him loss and damage as well.