The phrase "founded jointly" is grammatically correct and can be used in written English.
It means that something was created or established by multiple people or entities working together. Example: The company was founded jointly by two entrepreneurs with a shared vision for the future.
Clive Peedell co-founded and jointly leads the National Health Action party (NHA).
He jointly founded a lobbying firm and turned it into a Washington powerhouse.
The two cities (both on the island of Euboea) had jointly founded Cumae in Italy (c. 750).
The company was jointly founded by NBC Universal and the News Corporation — which both rely on fees from those distributors — and the private equity firm Providence Equity Partners in 2007.
The Moscow house project was initiated by the Velux Group, a Danish company that makes roof windows and solar panels and jointly founded an active house alliance last year.
Fontinalis Partners, a Detroit-based venture firm jointly founded by William Clay Ford Jr., and the venture capital firm LaunchCapital are among the lead investors in the expansion.
"The Last Sultan" follows the young Ahmet Ertegun into the music world and describes how he jointly founded Atlantic Records, the company over which he long presided.
The Farc's last attempt to contest elections after a peace process was during the late 1980s, when they jointly founded – with the Communist party – the Unión Patriótica.
Last May, with twin pledges of thirty million dollars, Harvard and M.I.T. jointly founded edX, a nonprofit MOOC company that works with a dozen colleges and universities, including U.C. Berkeley and Rice.
Investing in a Start-Up Prodisc was developed by Spine Solutions, a privately held start-up company in New York that was jointly founded in 1999 by a German medical instrument maker and a New York investment firm specializing in orthopedics, Viscogliosi Brothers.
