In the Wall Street dogfight between two billionaire investors, William A. Ackman won a moral victory but Carl C. Icahn won the war over the future of Herbalife, the nutritional supplements company.

On Friday, federal regulators imposed stiff sanctions on Herbalife for deceiving buyers and sellers of its products but stopped short of shutting down the company. Mr. Ackman had wagered big on Herbalife’s demise, while Mr. Icahn had been betting on its ultimate survival.

In a settlement with the Federal Trade Commission, Herbalife will pay $200 million in consumer relief, hire an outside monitor and make substantial changes to its business practices in the United States that could affect its bottom line, but the company will continue to operate.

For nearly four years, Mr. Ackman argued loudly and often that Herbalife was a pyramid scheme that took advantage of customers — at one point staking $1 billion on a decline in Herbalife’s shares in a characteristically brash move to prove his point. He gave numerous public presentations using hundreds of slides and videos to make his case that Herbalife was predatory. He even invoked members of Congress to pressure regulators to take action against the company.