In a financial climate already full of risk, there’s a new type of investor raising questions both on Wall Street and in Washington, D.C.: an “activist” investor whose profit depends not on the success of a company he targets but on its destruction.

For decades, investors have engaged in short selling, betting that the price of a stock will go down. If it does, the short seller makes a profit, sometimes a hefty one. In the past, the investor allowed the natural machinations of business and the stock market to determine whether a stock price rose or fell, but this new breed of activist investor pursues a different course. He shorts a stock, then does everything in his power to drive the price down to ensure he makes money.

Consider Steven Eisman, who became famous as one of the Wall Street figures about whom Michael Lewis wrote in The Big Short, his chronicle of the 2008 subprime mortgage meltdown. In 2011, after shorting stock in publicly traded for-profit colleges, Eisman approached the Department of Education and the U.S. Securities and Exchange Commission with damaging data about those schools. When he testified before the Senate Committee on Health, Education, Labor and Pensions, the for-profit colleges stock dropped — and he turned a profit. “Eisman,” one executive with a private sector college association told CNN, “[is] in the business of ruining the reputation of companies so he can make money when their stock prices drop.”

But what Eisman did pales when compared to the exploits of William Ackman, the founder of Pershing Square Capital Management, a $12-billion hedge fund. In May 2012, he took a $1 billion short position in Herbalife, the international company based in California that sells nutritional and weight loss products not through retail outlets but individual distributors. It operates on a multi-level marketing plan, like Avon and Tupperware. Now in 88 countries, Herbalife has been in business for 33 years. But in December 2012 Ackman went public with his attack on the company. His goal was simple: drive the stock price, then $52 a share, as low as possible.

With a $1 billion bet hanging in the balance, Ackman spoke at the Sohn Conference Foundation gathering, calling Herbalife a pyramid scheme, a fraud, “a modern-day version of a Ponzi scheme.” The company especially harmed the Hispanic and African-American communities, he said, since members of those groups were often targeted to become distributors and promised earnings that never materialized. Federal regulators should put Herbalife out of business, he declared; the stock price should plunge to zero.

The next day, the stock did slip but, early in 2013, something happened Ackman had not anticipated. Investor Daniel Loeb and financial legend Carl Icahn bought major stakes in Herbalife, eight and 13 percent respectively. That, in effect, blocked Ackman’s attempt to destroy Herbalife’s stock value.

So Ackman went on the offensive with an all-out assault on the company. “To pressure state and federal regulators to investigate Herbalife,” The New York Times reported, “his team…helped organize protests, new conferences and letter-writing campaigns in California, Nevada, Connecticut, New York and Illinois, although several of the people who signed the letters to state and federal officials say they do not remember sending them…. His team…also paid civil rights organizations at least $130,000 to join his effort by helping him collect the names of people who claimed they were victimized by Herbalife in order to send the leads to regulators.”

In June, Ackman convinced Rep. Linda Sanchez (D-Calif.) to write a letter to the Federal Trade Commission, asking for an investigation of Herbalife. In January 2014, he persuaded Sen. Edward MarkeyEdward (Ed) John MarkeyDem senators demand Trump explain ties to Koch brothers Overnight Cybersecurity: Senators want info on 'stingray' surveillance in DC | Bills to secure energy infrastructure advance | GOP lawmaker offers cyber deterrence bill Overnight Tech: Alleged robocall kingpin testifies before Congress | What lawmakers learned | Push for new robocall rules | Facebook changes privacy settings ahead of new data law | Time Warner CEO defends AT&T merger at trial MORE (D-Mass.) to write both the SEC and the FTC. The Sanchez letter had no effect on Herbalife’s stock, but the Markey letters caused the stock to drop 14 percent, the reason, after all, Ackman lobbied Markey in the first place. “Mr. Ackman’s staff acknowledges,” according to The Times, “that this crusade is really rooted in one goal: finding a way to undermine public confidence in Herbalife so that his $1 billion bet will produce an equally enormous return.”

Finally, some observers spoke out, convinced that what Ackman was doing was wrong. In March of this year, Anne Weismann, interim executive director of the Citizens for Responsibility and Ethics in Washington, a left-leaning watchdog group, wrote to Sen. John ThuneJohn Randolph ThuneHouse, Senate GOP compete for cash Overnight Tech: Alleged robocall kingpin testifies before Congress | What lawmakers learned | Push for new robocall rules | Facebook changes privacy settings ahead of new data law | Time Warner CEO defends AT&T merger at trial Senators grill alleged robocall kingpin MORE (R-S.D.), chairman of the Committee on Commerce, Science, and Transportation in the Senate, and Rep. Fred Upton (R-Mich.), chairman of the Energy and Commerce Committee in the House of Representatives, to request that their committees “investigate the ways short sellers are manipulating the government regulatory process for personal financial gain.”

Ackman “has gone to unprecedented lengths to urge federal regulatory action against Herbalife,” Weismann noted. “It now appears that Mr. Ackman’s campaign against Herbalife is the subject of a Department of Justice inquiry. While [he] may have engaged in illegal market manipulation…the question of whether Mr. Ackman — among others — has attempted to manipulate federal regulators and even members of Congress to move the price of stock in which he has an interest should be of concern….”

It’s a problem Congress should care about. “Americans already believe both Wall Street and Washington are rigged,” Weismann concluded. “Watching billionaire hedge fund managers utilize their vast resources to instigate government investigations to increase their wealth can only lead to even further decreased confidence in the country’s financial markets and government leaders.”

Meanwhile, Ackman continues his war on Herbalife — so far with modest results. The stock is trading at $43 a share, only seven dollars down from when he began his attack. But he shows no signs of letting up, unless Congress intervenes.

Alexander, as former Time reporter, is an editor and an author.