Winklevoss twins invest in social network SumZero

The Winklevoss in a recent TV commercial for pistachios.

/ YouTube

(CNET) The Winklevoss twins, best known for their courtroom battles with Mark Zuckerberg over Facebook, are taking another stab at the social-networking sector.

Tyler and Cameron Winklevoss have made a $1 million investment SumZero, a social network aimed at professional investors, The Wall Street Journal reports. The company was founded in 2008 by former Harvard classmates Aalap Mahadevia and Divya Narendra, the latter of which was a party to the Winklevoss twins' lawsuit that claimed they were misled about Facebook's value.

The case stemmed from a settlement the Winklevosses and Narendra signed with Facebook in 2008 after claiming Zuckerberg stole their idea for a social-networking site they called ConnectU, the basis for the 2010 movie "The Social Network." The trio accepted a $65 million settlement from Facebook and Zuckerberg in exchange for dropping all further litigation against the site but later said the settlement was based on an

Microsoft's Facebook stake influenced ConnectU case

As Facebook gets ready to put ConnectU behind it, some details surface about the role Microsoft's $240 million investment played in the legal proceedings.

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They filed suit to undo the pact after it was revealed Microsoft paid $240 million in 2007 to acquire a 1.6 percent share of Facebook, giving social network a $15 billion valuation. The Winklevoss twins and Narendra claimed they were led to believe that Facebook's valuation was about a quarter of that.

The 9th U.S. Circuit Court of Appeals

Facebook foes lose appeal

Cameron and Tyler Winklevoss, who accused Mark Zuckerberg of stealing the idea for Facebook, lost their latest appeal to contest a 2008 $65 settlement between the parties.

last year, upholding the 2008 settlement. The trio threatened to take their case to the U.S. Supreme Court but later retreated and

Winklevoss twins drop Facebook lawsuit

The former classmates of Zuckerberg decide to drop their long-running legal dispute against the social-networking giant and its co-founder and accept a $65 million settlement.

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In February, the twins

And, poof, the Winklevoss twins become VCs

, and their first investment in June was SumZero. The site, which claims about 7,500 members, accepts only investors who work on the "buy side" -- hedge funds, mutual funds, and private-equity firms. Wall Street bank analysts are not allowed.

The site, which says it rejects 75 percent of those who apply, allows users to follow each other's activity and requires members to regularly submit trading ideas to the network. Those who don't lose access to the database, the Journal reported.

This article originally appeared on CNET under the headline "Winklevoss twins get back to social networking with investment."