Online brokerage firm ShareBuilder Corp. continues to generate growth for ING Direct even as the company’s credit union clientele has decreased.

That’s according to ING Direct spokeswoman Cathy MacFarlane. ShareBuilder was bought by ING Direct in 2007. At the time of the sale, the broker had 125 credit union clients. In January, that number had dropped to 50 as ING Direct made adjustments with its co-branded partnerships.

MacFarlane said over the past two years, ShareBuilder has streamlined the financial-based partnership program down to a short list of relationships. Those alliances have “strong online membership in line with ShareBuilder and ING DIRECT’s online service offering and target demographic,” she added.

“It’s important to note however that ShareBuilder continues to honor the relationship with all the retail customers of credit unions that were previously part of the partnership program,” MacFarlane said.

ShareBuilder’s parent company ING announced today that it would sell PrimeVest Financial Services and two other independent broker-dealers. PrimeVest serves nearly a dozen credit unions. As for ShareBuilder, MacFarlane said the online firm has seen a 140% increase in account growth year over year.

“ShareBuilder is a grow engine for the ING Direct business and our CEO, Arkadi Kuhlmann, has stated that he anticipates the business will continue to hire and expand,” MacFarlane said.