Seccl was founded in a garden shed by Dave Harvey and Hugo Thorman after the pair left platform Ascentric, later sold to M&G which dropped the Ascentric brand in 2021.

Mr Thorman was CEO of Ascentric and Mr Harvey supported in senior technology roles.

The two Seccl founders have built a company based on the latest technology with cloud-native and API-first software principles. It focuses on offering low costs.

Financial details of the share change have not been released but Seccl has confirmed that Octopus has now increased its stake to over 90%.

Seccl has become popular with a number of businesses including Financial Planning firms. Financial Planner Cooper Parry Wealth was the latest firm to adopt Seccl, announcing a deal last week to use Seccl as the base for its in-house platform.

Octopus acquired Seccl in 2019 while it was still pre-market and has supported the growth of the firm. Since then Seccl has developed new products and tools, including a fully automated SIPP launched last year.

David Ferguson, previously founder and CEO on platform Nucleus, joined Seccl as CEO in 2022.

Mssrs Harvey and Thorman will leave on 11 March after deciding it was the right time to sell their stakes, Seccl said. This size of the pair's stake has not been disclosed.

Mr Thorman said: “It has been a career highlight to work with Dave to deliver the change our industry so desperately needed. And while I’ll be moving on, I won’t be moving far – I look forward to continuing to interact with Seccl in my position as chair of P1 Investment Management.”

Mr Harvey said: “I started Seccl with the belief that change was desperately needed and having taken that idea from its humble beginnings in a garden shed to where the company is today, it feels the right time to step away. Under David’s leadership and with an experienced and now well-embedded senior team, I know that the company is in safe hands – and have every faith that it will continue to flourish.”

David Ferguson, CEO of Seccl, said: “Dave and Hugo have built a special legacy for which we are all indebted – not just Seccl but the market at large. There are very few people who make the leap and take a chance on something entirely new. They did – fuelled by Dave’s extraordinary vision, drive and unwavering belief in better, and commercialised by Hugo, a pillar of our industry who it has been great to work alongside as an accomplice, after many years in competition.

Octopus is valued at £12.5b and owns companies such as Octopus Energy, Octopus Investments and Octopus Money.  

Financial Planning Today Analysis: Today's announcement makes sense for the Seccl founders who want to cash in and move on after five years building a formidable business. Seccl is becoming popular with a new wave of smaller, often in-house white labelled platforms. Its hi-tech approach and relatively low costs are attractive to Financial Planning firms and others seeking to enjoy a piece of the platform pie without some of the huge costs associated with platforms. Legacy platforms, often encumbered with older technology and creaking computer systems, will need to move quickly to avoid being caught out by an industry disruptor.