In the space of a few hours on Tuesday, CAA suffered the biggest blow to its image as Hollywood’s invincible powerhouse since the agency was shaken 20 years ago by the departures of co-founders Michael Ovitz and Ron Meyer.

UTA has recruited at least 13 CAA agents to its fold, all of them focused on comedy stars active in film, TV and touring. The staffers are in the process of relocating en masse from CAA’s Century City highrise to UTA’s Beverly Hills compound. The stealth move was akin to a smaller nation mounting a strategic strike on a neighboring superpower.

CAA sources said agency leaders were livid and promising to pursue legal action, with sources insisting that defecting agents were all under contract. UTA leaders were bracing for the possibility of a legal challenge but sources said the agency was confident that their new hires were unencumbered and free to make the move.

Jason Heyman and Martin Lesak, who ran CAA’s comedy division, are taking many of their employees with them to UTA. The comedy duo will also become UTA partners, alongside former CAA agents Greg McKnight, Greg Cavic and Nick Nuciforo. The hires add still more firepower to UTA’s formidable roster of comedians, actors, writers and producers.

The shakeup also means that dozens of coveted clients are likely in play. Already on Tuesday, Chris Pratt and Will Ferrell were confirmed as following Heyman and Lesak to UTA, as were Jim Parsons and Vin Diesel. Melissa McCarthy, one of the biz’s most bankable B.O. stars at present, was considered in play as of late Tuesday.

Heyman, Lesak and McKnight are returning to UTA after spending the past 10 years with CAA.

Nuciforo is a top player in the highly lucrative world of standup comedy tours — an area that UTA was eager to expand into given its roster of comedy talent.

The defections reveal the mounting frustration within CAA’s marbled halls that the top managing partners who run the agency have profited handsomely from a series of equity sales during the past five years that have left private equity giant TPG Capital as the agency’s majority owner.

CAA sold a 35% stake to TPG in 2010, just as it began an aggressive, capital-intensive expansion into the sports talent and marketing arena, in the U.S. and abroad. Last October, TPG acquired another unspecified stake in the agency.

While CAA leaders have insisted that the ownership structure has not affected the management of the agency or its team-oriented culture, Tuesday’s dramatic departures are evidence that some staffers are voting with their feet. In the past, industry insiders noted, it was rare that agents would leave CAA unless they were eased out.

Other confirmed CAA-to-UTA defectors are Susie Fox, Joanna Scott, Jon Saks, Chelsie McKinnies and Mackenzie Condon. Rachel Rusch, Matt Blake, Matt Frost and Ryan Abboushi are possibly leaving as well.

Industryites and reps at rival agencies followed Tuesday’s blow-by-blow with unabashed glee. One veteran agent at a rival to CAA and UTA described the situation as “karma” for CAA given the agency’s wooing away top agents from other shops with lucrative contracts and the allure of working for Hollywood’s largest and glitziest shop.

Sources say the agents who are leaving were frustrated over compensation and the lack of opportunities to rise within CAA’s hierarchy. Industry sources speculated that CAA’s notoriously insular culture that encourages staffers to keep a low profile began to chafe on Heyman and Lesak in particular.

The last time CAA faced such a public crisis in its ranks was the summer of 1995, when its larger-than-life leader Ovitz and Meyer surprised the industry by bolting for top studio jobs. Meyer left in July 1995 for the top job at Universal Studios — a post he held until last year when he shifted to vice chairman. Ovitz left for what would prove to be a tumultuous 14-month tenure as president of the Walt Disney Co.

The fallout from the Ovitz-Meyer shakeup shaped the core of the leadership team that runs CAA today, lead by president Richard Lovett and managing partners Kevin Huvane, Steve Lafferty, Bryan Lourd, David O’Connor and Michael Rubel. [Variety]