In a statement, it said it will cease to be a member of the organisation at the end of this year.
It said: “Legal & General’s business has evolved over time, and now a large proportion of its business lines fall outside the remit of the ABI. In the future we believe engagement with government, regulators and other external bodies will be more individually tailored, and less suited to uniform representation through one trade body.
“We believe the ABI plays an important role in public policy formulation for the sector, and in promoting best practice and codes of conduct across the sector. We would like to work with the ABI on these important issues.”
It is also understood L&G believes it can lobby more effectively on significant business issues by itself. Chief executive Nigel Wilson will also step down from the ABI board. The ABI itself was, until two years ago, chaired by Wilson’s predecessor Tim Breedon.
Earlier reports said sources speculated that the recent split of the ABI’s investment affairs mandate, which is responsible for corporate governance, was likely to be a factor in L&G’s decision.
ABI director-general Otto Thoresen, said: “As a trade association, of course we are disappointed by the resignation of a member, however, the ABI’s continuing strong membership represents over 90% of the insurance sector.
“The great advantage of the ABI is that our members work together across the usual corporate boundaries to tackle issues that are important to consumers and to deliver an agenda for reform.”
The ABI has about 300 members and represents 90% of the UK insurance market.