Internet Capital Group

(ICGE)

said Wednesday that it will use $635 million worth of its highflying stock to acquire a majority interest in a Web software company, ICG's biggest deal in a recent spate of agreements for the business-to-business Web company.

RightWorks

provides e-procurement software for B2B exchanges, an increasingly hot sector of the Internet economy.

"RightWorks is the emerging industry standard to operate B2B exchanges, and we have joined forces with RightWorks to accelerate the adoption of its technology by market makers worldwide," said Mary Coleman, managing director of ICG who will join the RightWorks board once the deal is completed.

The transaction to acquire the privately held, San Jose, Calif.-based firm also includes $22 million in cash.

The deal tops a $450 million stock swap ICG announced two weeks ago to acquire

eCredit.com

, a start-up that handles online credit information used by businesses.

ICG, a Wayne, Pa.-based Internet incubator that owns more than 55 B2B Web companies, went public last year. Wednesday, its shares closed down 3 1/32, or 2.15%, at 138 1/8.