Cofunds sales and marketing director Alastair Conway is leaving the platform after five years.
Conway, who joined in January 2008, said he would be pursuing an opportunity within the industry he said he "simply couldn't turn down", though not at a rival firm.
"Clearly if I was going somewhere that was going to compete with they would be asking me to leave a bit quicker," he said.
"It's been a very amicable process about me moving on - we've all worked very closely together and that hasn't changed in the last few weeks. It's my long term experience that is probably the key to what I do next."
Conway was previously head of proposition as network giant Sesame and CEO of Clear Group, an IFA firm.
The platform is to split sales and marketing roles, meaning a replacement for Conway will not be sought.
Head of proposition Verona Smith will become director of marketing, with head of investor and wealth distribution Andy Coleman also becoming a director.
CEO Martin Davis said: "Alastair has achieved a great deal during his time here. We're very grateful for the contribution he's made and are sorry to see him go, but this is a great opportunity for him so wish him all the best in his new role."
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