By Sarah McBride

SAN FRANCISCO, Oct 31 (Reuters) - Benchmark, the firm behind companies ranging from eBay to Twitter, is raising a new venture fund, according to a person familiar with the situation.

The fund will be about the same size as Benchmark's previous fund, a $425 million vehicle that closed in January 2011, the person said.

"Benchmark is committed to maintaining a laser focus on early-stage investing," said general partner Bill Gurley in an emailed statement to Reuters.

"We maintain a consistent and intentionally limited fund size, which is best managed through long-term relationships with a limited number of limited partners. Given this structure, the actual beginning and end of a specific fund is not a noteworthy event."

Investors consider Benchmark one of the top-performing venture firms, on par with bigger players such as Greylock Partners and Sequoia Capital, which have each raised more than $1 billion this year. Venture firms generally do not disclose their performance to the public.

Benchmark was a relatively early investor in Twitter, backing the nascent message service in 2009. It holds 6.6 percent of the company, which is expected to hold its initial public offering next week. The IPO is expected to value Twitter at up to $11 billion.

Benchmark's other investments include transportation service Uber, review service Yelp, and real-estate service Zillow.

The new fund will be Benchmark's eighth. The firm was founded in 1995.