Over the past year, Marc Andreessen invested in a series of high-profile Web companies, including Facebook Inc., Twitter Inc. and Groupon Inc. Now the Silicon Valley venturecapitalist is hitting the pause button on such big-name deals.

Since participating in a $112 million funding of Web darling Airbnb Inc. in July that valued the online room-rental company at more than $1 billion, Mr. Andreessen said his venture-capital firm Andreessen Horowitz has 'taken a step back.'

With some deals for private companies 'definitely on the expensive side' amid a choppy stock market and concerns over a European debt crisis, Mr. Andreessen said he is looking to invest in fast-growing tech start-ups that aren't as well known and where 'pricing is still under control.'

Mr. Andreessen is the most visible of a group of venture capitalists dialing back on certain deals after a breathless year of venture investing that had some comparing 2011 to the late 1990s dot-com bubble. Many venture capitalists said they now are increasingly passing on companies seeking frothy valuations, and some are trying to get off the beaten path to find cheaper deals.

While there still is clamor to invest in the best-known and priciest start-ups