MADRID — Ensuring a glitzy get-go to its 60th edition, ”Arbitrage,” starring Richard Gere and Susan Sarandon, will screen as the opening gala of this September’s San Sebastian Festival, the biggest fest in the Spanish-speaking world.Gere and Sarandon are both expected to return to San Sebastian, having picked up career-achievement Donostia Awards there in 2007 and 1995, respectively. The fiction feature debut of Nicholas Jarecki, ”Arbitrage,” a withering Wall Street morality-thriller, also features Tim Roth, Brit Marling, Laetitia Casta and Nate Parker. Pic will play in competition. Produced by Laura Bickford, Kevin Turen, Justin Nappi and Robert Salerno, it was acquired for the U.S. off its Sundance Festival premiere by Lionsgate and Roadside Attractions. Sold by Parlay Films, ”Arbitrage” has struck heavyweight distributor deals in major territories such as France (Metropolitan Films), Germany (Wild Bunch), Latin America (Swen group Intl.), Scandinavia (Svensk Filmindustri) and Spain (Tripictures). Helmer of Showtime docu ”The Outsider,” a portrait of filmmaker James Toback, Jarecki co-wrote and exec produced Bret Easton Ellis adaptation ”The Informers” and exec-produced Toback’s intimate portrait ”Tyson,” which won a Knockout Award at Cannes’ 2008 Un Certain Regard. The San Sebastian Festival runs Sept. 21-29.