After a dismal 2009, venture capitalists are preparing to ramp up their investments, injecting much-needed cash into start-ups.

Some venture capital firms have loosened their purse strings in recent weeks and are starting to invest new money. That has resulted in several deals, such as last month's $52m (€36.4m) infusion into social-networking advertising and software company RockYou and the $57m invested in online textbook-rental service Chegg.