Sigma Partners, a Menlo Park, Calif. venture capital firm, has raised a $500 million to invest in new companies, according to PE Wire.

This is the firm’s eighth fund. Its most recent fund was $400 million, and so the firm is following a widely adopted practice within the industry of raising larger funds over time. They more money a firm has to manage, the more fees its partners get from its investors to manage the funds.

VentureWire has more:

The firm has yet to see any exits from Sigma 7 [its most recent fund], but m-Cube, a Watertown, Mass., company backed from fund six – a $600 million vehicle assembled in 2001 – was acquired in May 2006 for $250 million by publicly traded VeriSign Inc. M-Cube’s technology helps companies develop, deliver and bill for mobile content, messaging and applications.

Another fund six company, EqualLogic Inc., a Nashua, N.H., provider of storage products designed to simplify how companies retain, access, manage and protect their data, has filed to go public. Virtusa Corp., a Westborough, Mass., information technology-services provider backed through Sigma’s $300 million fifth fund, went public in August.