Interactive Investors says the deal will increase its platform Assets Under Administration (AUA) to about £50bn and increase its number of customers to more than 400,000.

The EQi deal will add about £5bn in AUA and 50,000 clients.

Interactive has expanded rapidly in recent years. It bought TD Direct Investing in 2017, ATS in 2019, and The Share Centre’s owner last year. 

Interactive says it has seen record levels of new customer subscriptions and asset flows in the past year.

Interactive investor offers ISAs, SIPPs, Junior ISAs and general investing accounts, plus investment content, tools, choice and service. 

Customers pay a flat monthly fee regardless of their investment portfolio size. 

The EQi brokerage business is flat fee and customers will continue to be able to use from Interactive Investor’s flat fee model, says Interactive.

Interactive Investor is majority owned by funds advised by private equity firm JC Flowers & Co and currently has assets under administration of £45 billion and over 350,000 customers. 

Richard Wilson, CEO of Interactive Investor, said: "I am delighted to announce the acquisition of EQ’s retail investment business and look forward to welcoming EQi customers to the ii platform, where we hope they will benefit from our no-nonsense fixed fee pricing, commitment to service and continuously developing technology and content.

“This marks another important milestone in the ii story, having brought together five established investment businesses within the last four years to create a single market-leading platform that offers the retail investor real choice and value.

“We feel privileged to serve EQi customers and, as a matter of course, if, six months from migration, we find that they would have paid less under EQ’s charging model, we will refund the difference.”