• First part of $250m investment to fund offices in three cities

• Journalism site to have both nonprofit and for-profit entities

Pierre Omidyar, the founder of eBay, is injecting his first $50m into the new journalism venture he is setting up with former Guardian columnist Glenn Greenwald.

The investment represents the first tranche of a total pot of $250m that the billionaire entrepreneur and philanthropist has promised for the new operation. A statement released from Honolulu on Thursday said that the money was being used to set up offices in New York, San Francisco and Washington.

The holding company, which has changed its name from NewCo to First Look Media, seeks to build on Greenwald’s growing following in the wake of his work on the Edward Snowden leaks of National Security Agency documents to generate what it calls “robust coverage of politics, government, sports, entertainment and lifestyle, arts and culture, business, technology, and investigative news”.

The venture has revealed new details about its nascent structure. On the one hand, the journalism site – which has yet to be named – will be constituted as a nonprofit organisation with a tax-exempt 501 (c)(3) status and will have, the press release says, editorial independence.

But running alongside it, a profit-seeking company will also be established that Omidyar and Greenwald are billing as a “media technology” concern. Any profits generated by this company will go towards supporting the independent journalism.

Jay Rosen, a New York University professor who is acting as adviser to First Look Media, gave his interpretation of the business structure in his blog Press Think. He compared the nonprofit / profit duality of the venture to the structure of the Guardian Media Group – a profit-making business that is fully owned by a trust and that channels its earnings to support the independent journalism of the Guardian.

He also compared it to Bloomberg News that is in part supported by profits from the commercial income from Bloomberg terminals.

“First Look Media is adding to the picture another possible source of support: profits from a company specifically focused on technology for producing, distributing and consuming news, views and information.”

Greenwald has the star billing in the new operation. Also on board is Laura Poitras, the Berlin-based film-maker who has been heavily involved in coverage of the Snowden leaks.

Other early signings include Jeremy Scahill, former national security correspondent of the Nation, and former Huffington Post and Washington Post journalist Dan Froomkin.