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By Selena Simmons-Duffin

Several hundred people showed up this afternoon at the Menlo Park offices of the buyout firm, Kohlberg Kravis Roberts & Co., to protest what a spokesperson called "special perks and tax loopholes that buyout firms depend on to make billions."

The protest at 2800 Sand Hill Road was one of many organized by the Service Employees International Union in cities such as New York, Bangalore and Paris, the union said.

People held signs reading "End KKR Greed" and "Take back the economy." Some passing drivers honked their horns.

In a press release, the union said "the buyout industry's high-risk business model and use of lucrative tax breaks … bleed money from state and federal treasuries."

An unnamed representative of KKR appeared at the protest and was handed a giant check, written to U.S. taxpayers for the billions of dollars the union says is owed by KKR due to tax loopholes. The KKR representative made no comment.

While police in riot gear were called out, and the protest was hectic and loud, there was no violence and no one was arrested. In fact, a police officer was overheard thanking protestors for being peaceable.

The scene of the protest, which lasted about an hour, is the West Coast headquarters of KKR.

"These are long battles but the critical outcome was to let KKR know that people are watching," Jono Shaffer, private equity field campaign organizer for SEIU, said in an interview. "We have hundreds of thousands of SEIU workers whose retirement savings are in the funds that KKR uses to invest."