Nucleus has reached a deal with Bravura Solutions which will see the platform get direct access to the technology underpinning its services.
The platform's access to Bravura's Sonata application has, to date, been provided through an outsourcing agreement with OpenWealth but with the new long-term deal Nucleus will have a direct contractual relationship with Bravura.
Nucleus has said this will improve the control it has over its technology and allow it to accelerate the rate of product development for its users. This would in turn will help it drive future inflows and assets under administration growth.
Andrew Smith, chief technology officer at Nucleus, said: "This new arrangement is of vital importance to the ongoing process and pace of development at Nucleus as we prepare the business for significant scale in our second decade in business.
"By working with Bravura directly, we believe we will be able to better deliver regular platform updates that will substantially improve propositional and regulatory change for the benefit of our users and their clients."
Nucleus has said the new arrangement is predicted to be "broadly cost neutral".
OpenWealth will continue to provide Nucleus with business process outsourcing services including account servicing and administration.
Tony Klim, chief executive of Bravura, said: "We have been working with Nucleus since it launched and we are pleased to see the relationship develop to this point.
"Sonata enables Nucleus to connect and engage with their clients anytime, anywhere, using their choice of device. We hope that by working directly with us, Nucleus will be able to develop their technology further to benefit its users positively."