Cardiff-based Culver Insurance Brokers is to move its whole general insurance division to the Acturis broker platform.
Culver, which recently left the Willis Commercial Network, said all 34 members of the Culver team are now trading on Acturis.
John Powell, Culver chief executive, said: "We were at a point where we had to decide whether to renew our deal with Willis or opt for independence. Although we are very grateful for the support of the Willis Commercial Network over the years, we felt as a team that our future looked brighter outside the network.
"The choice of a tried and tested IT system to support our ambitious growth plans was a significant part of that final decision."
Acturis co-chief executive, Theo Duchen, said: "We are delighted that such a prominent broker as Culver has selected Acturis. Culver is well-known in Wales and the South West, as well as across the Willis network. We will be working very closely with Culver to ensure that they extract the maximum benefit from the use of the Acturis broker platform."
Acturis serves 100 broker sites in the UK, and user numbers now stand at around 1,600.