Bay Area (Map, News) - Confidence in the local economy among venture capitalists is at a four-year low, according to a quarterly index published by the University of San Francisco.

“VCs expressed concern over the volatile credit markets and potential broader economic decline – conditions which may make venture exit opportunities more difficult.” said Professor Mark Cannice of the University of San Francisco School of Business and Management, the study’s author.

The index, based on a survey of 28 Bay Area venture capitalists, registered a 3.54 out of a possible 5 for the fourth quarter of 2007, a sharp drop from the 4.15 reading of the previous quarter and the lowest in the history of the index.