With the broader economy sputtering, venture capital firms are finding it increasingly difficult to generate returns through the sale or public listing of portfolio companies. In the second quarter of 2008 there were no initial public offerings (IPOs) of U.S. venture-backed companies. Moreover, liquidity generated via mergers and acquisitions (M&As) fell to $4.7 billion with just 56 transactions completed, according to the Quarterly U.S. Liquidity Report released by Dow Jones VentureSource.