New York--Capital Z Partners, New York, and General Atlantic Partners, Greenwich, Conn., announced a $300 million joint venture to invest in e-commerce financial services initiatives. Dubbed efinanceworks, the business will help start-ups and Fortune 500 companies staff and launch new Internet businesses. The company has leased a large office space in New York City, but has not yet identified its first investment. Capital Z and General Atlantic are 50-50 partners, each investing $150 million apiece. The companies said inefficiencies in the financial services sector make it ripe for Internet build-out. The company will rely on expertise from McKinsey & Co. and Internet consultant Proxicom to help shape its investments. In setting up the venture as an incubator--the partners call it an accelerator--efinanceworks follows the model employed with success by idealab!, Pasadena, Calif., and numerous Silicon Valley venture capitalists.