BURLINGTON,Cliffstone Corporation, a developer of employee performance management software, has been sold to Performix Technologies.

As part of the deal, 14 Cliffstone clients and its proprietary software will be transferred to Performix.

Stephen Beckett, founder and chief executive officer of Cliffstone, also will join Performix as vice president of product strategy.

Cliffstone clients include Sprint, American Express, DirecTV and SBC. It was founded in 1997 and is based in Woodstock, GA.

Performix: www.performix.com