Around this time, Winx Club's international success attracted the attention of the American media company Viacom, owner of Nickelodeon and Paramount Pictures. In February 2011, Viacom became a co-owner of Rainbow, purchasing 30% of the company and leaving the remaining 70% to Iginio Straffi. Viacom's entry into the company followed a "long courtship," and the terms of the US$83 million purchase were decided earlier in 2010. Viacom provides Straffi access to financial and studio resources that, according to L'espresso, "ensure the future of the Winx fairies, and of Straffi himself." L'espresso called the transaction "Straffi's most important agreement," as it led to the worldwide distribution of Rainbow's shows through Viacom's network of subsidiaries. Viacom's Nickelodeon studios have co-produced various projects with Rainbow, including additional seasons of Winx Club and Club 57 in 2019.
When asked by an interviewer in 2011 if he was "tired of" working on Winx Club, Straffi responded, "Let's just say I've moved onto other projects." His other creations include the horror comic book series Maya Fox (first published in 2008) and the animated television series Huntik: Secrets & Seekers (which premiered in 2009). In 2012, Straffi's first original animated film, Gladiators of Rome, opened in Italy. The movie was one of the most expensive Italian films made at the time, costing around $80 million (70 million euros) including marketing costs. The film performed poorly at the box office, earning about $10 million worldwide, which Straffi assumed was a result of Rainbow's lack of experience with cinema. Iginio Straffi also produced The Dark Side of the Sun, an animated documentary that premiered at the Rome International Film Festival in December 2011.