Mr Coyle was poached by Aegon in 2012 to head platform sales in the run up to the launch of its Retirement Choices platform.
He had previously worked in senior roles at Axa Wealth and Prudential.
An Aegon spokeswoman said: “Martin left the business recently and we wish him all the best for the future.
“He left following a review of the operating structure of our distribution function last year.
“The changes were designed to ensure our retail business is well organised to deliver support to advisers and promote Aegon’s products and services.”