Registered investment advisors will soon have more ammunition in their battle against the wirehouses.

Shareholders Service Group, which provides brokerage and custodial services for independent registered investment advisors, will begin providing Black Diamond’s web-based portfolio management and reporting platform to its clients.

“Many of our clients are in growth mode,” Peter Mangan, SSG’s chief executive and president said in a statement announcing the deal yesterday.

Access to the web-based platform will “enable them to enhance client service, improve productivity and scalability as they grow,” he said.

Advisors working with SSG will be able to access Black Diamond on SSG’s technology platform.  The program will be communicated to SSG clients through a series of web casts and online events.

“Adding Black Diamond will enable advisors working with us to be on the same playing field and successfully compete with the industry’s largest wealth management institutions,” Mangan said.

Insiders credited Dan Skiles, who recently joined SSG from Charles Schwab’s RIA business, where he was chief tech officer, for putting the deal together.