Freeserve will provide the service with three partners - GlobalNet of the United States, Canada's First Marathon and the Chicago-based financial services firm Mesirow Financial.
As well as offering online securities trading and brokerage to retail investors it will provide clearing services to British brokers with the potential to expand in the future into other parts of the European Union.
"We are very pleased to be part of this rapidly growing revenue generating business that will take advantage of access to more than 1.32 million Freeserve accounts," said John Pluthero, chief executive. The move follows a decision two weeks ago by Freeserve to offer foreign exchange dealing through GlobalNet Financial.com.
Shares in Freeserve, which floated last month at an issue price of 150p, climbed 7.5p yesterday after the deal was announced, before falling to close unchanged at 208p.
Freeserve joins the Halifax and Prudential, which have both already hatched plans to launch online share trading.
The new online share broking facility will have a link to Freeserve's Money Channel, UK-iNvest.com, which is owned and operated by GlobalNet.
Mesirow will provide expertise in securities trading and clearing while the investment firm First Marathon is expected to bring skills in account management and service.
The Freeserve venture is subject to regulatory approval from Britain's Securities and Futures Authority.