On March 29th, 2014, the Federal Reserve Board of Governors in Washington D.C. received an aggressively written, pointed letter detailing weaknesses in the current regulations governing the largest banks’ commodities business. Ten days earlier, the Federal Deposit Insurance Corporation had received a similar one arguing to strengthen the government’s ability to break up too-big-to-fail banks, a topic made even more relevant by the American megabank Citigroup’s failure to pass the Federal Reserve’s financial stability “stress test” on March 26th.

Though both letters were written in dense technical detail, grounded in deep knowledge of their subjects, neither was written by a private organization or lobby group. Instead they were penned by an informal group of unpaid volunteers of various ages and professional backgrounds called “Occupy the SEC” — a diverse assortment of amateur and professional financial reform advocates who meet once a week online or occasionally in person on scrounged plastic chairs in the lobby of 60 Wall Street.

When the Occupy movement emerged in the fall of 2011, it was mostly associated with the famous encampments that spread across the country. However, the individuals who formed Occupy the SEC that November chose a different form of activism. They spoke the language of financial regulation to the government institutions that make the rules for the very same Wall Street their fellow Occupiers were protesting. And unlike the movement as a whole, they never really stopped.

Heralded at the time as some of the most effective activists for financial reform within the Occupy movement, they’re one of the few Occupy groups that have continued their work unabated long after the rest of the movement mostly foundered, churning out an impressive volume of criticism, analysis and commentary aimed directly at the most powerful regulatory bodies in the U.S. government.

With very few exceptions, these institutions have been accustomed to receiving comment letters exclusively from representatives of the large financial institutions subject to regulation and a handful of public interest non-profits, rather than from concerned citizens. At least, until Occupy the SEC began their advocacy in November 2011.

“We’re an unincorporated association,” says Akshat Tewary, a soft-spoken Queens native who works in New Jersey as an immigration lawyer and FINRA arbitrator and has been part of the group since the beginning. “That’s our official term. There are other groups who do the same work, like Better Markets, Americans for Financial Reform and Public Citizen. But they’re all well-funded non-profits.”

Occupy the SEC is composed of between five to twelve active members at any given time, including lawyers, students, amateur financial wonks, and at least one active financial professional who prefers to remain anonymous, but sometimes uses the name “George Bailey.” Tewary and former US Marine-cum-financial regulation activist Eric Taylor are the two original members who have been publicly active in the group’s work since the beginning. Many of the other members prefer to stay out of the public eye.

Despite their status as the only all-volunteer financial regulation public interest group in the United States, Occupy the SEC has covered a wide array of extremely technical financial topics, from proprietary trading to IPOs to the LIBOR scandal and JP Morgan’s “London Whale” trading loss. Their greatest success so far was their much-praised 350-page letter in February 2012, calling for more stringent restrictions on banks’ proprietary trading activities in the 2010 Dodd-Frank financial reform bill, also known as the “Volcker Rule.”

Shortly after the letter’s publication they were unexpectedly invited to Washington to meet former Fed chairman Paul Volcker in March 2012, where they also met representatives from the FDIC, Securities and Exchange Commission, Federal Reserve Board and Office of the Comptroller of the Currency, along with a phone discussion with the Commodity Futures Trading Commission. “The agencies thanked us for our Volcker commentary and each of them asked questions that showed they had read the letter very carefully,” says Tewary. The letter was eventually cited 284 times in the final version of the law.

Their impact has continued to be felt in Washington, bolstered, they believe, by their unique status as unpaid policy-oriented citizen activists. In September last year, the SEC cited a February 2013 comment letter written by Occupy the SEC while issuing new rules governing the massive and sometimes unwieldy money market fund industry.

“We’re keeping busy with comment letters, amicus briefs and letters to Congress,” said one regular participant, a regulatory lawyer who preferred to remain anonymous. “And some of our strength and credibility comes from our status as citizen activists. I know that the regulators sometimes appreciate a non-establishment voice; it forces them outside the terms of the existing consensus.”

Financial policy advocate Bart Naylor, of the prominent Washington D.C. public advocacy group Public Citizen agrees: “Occupy the SEC provides articulate authoritative analyses of complex banking rules that command the attention of key policy makers,” he says. “In the final Volcker Rule, one of the keystones of post-crash reform, regulators cited the Occupy comment hundreds of times. In meetings I’ve had with regulators, the positions and arguments of Occupy figure prominently.”

The group is currently drafting a letter to the FDIC to argue that in a future financial crisis, any bank that is broken up should limit executive pay and give management control to the US government. Three years into their prolific advocacy work, they’re also reluctantly considering incorporating as a non-profit entity. “We need a Wall Street watchdog group keeping an eye on the street in New York,” says Elizabeth Friedrich, a former member who now works as a law clerk for Senator Carl Levin’s Subcommittee on Permanent Investigations. “All the groups that work on these issues are in D.C.”

Despite the fact that their efforts go without pay or very much outside recognition, the group shows no lack of motivation. “I think a lot of the Occupy groups suffered from being withdrawn from the frenetic energy that was there at the beginning,” says Tewary. “But we remain dedicated to financial reform. Maybe even more so now, because banks are more consolidated than ever before.” The anonymous regulatory attorney concurs, “The necessity of this work is clear to me when I read the news. Whatever your ideology, you can see that millions are out of work, corruption is endemic, and the risk of a future calamity is high.”

In our increasingly credentials-obsessed society, where well-heeled “wonks” with an insider’s perspective dominate the policy conversation, Occupy the SEC show that outsiders can make a difference, even when their ideas are opposed by a vast array of moneyed interests. Perhaps the lesson to be drawn from their work should be that if you can’t join ‘em, beat ‘em.

Charles Reinhardt works at NYU’s Arthur L. Carter Journalism Institute by day and is an MPA student at NYU’s Wagner School of Public Service by night. His writing has appeared in Maclean’s, Jacobin, The Barnes & Noble Review, Christian Science Monitor and Vol. 1 Brooklyn.