Tether and Bitfinex manipulation lawsuit entered public view

A putative class-action complaint accusing Bitfinex, Tether and affiliated parties of manipulating cryptocurrency markets became public news on October 7, 2019, pushing a long-running argument about the USDT stablecoin into federal civil litigation. The pleading itself was electronically filed in the U.S. District Court for the Southern District of New York on Sunday, October 6, under case number 1:19-cv-09236. Its significance on October 7 was therefore disclosure and market-wide scrutiny, not a court finding that the accusations were true.

The plaintiffs alleged that the defendants issued USDT without equivalent dollar backing, moved it onto Bitfinex and used it to buy cryptocurrencies when prices were weakening. According to the complaint, that activity created artificial demand, inflated prices and injured buyers of bitcoin and other crypto assets. The plaintiffs sought to represent a class and pleaded claims including alleged violations of federal commodities, antitrust and racketeering laws, along with fraud and other claims.

Those were allegations at the opening of a case. No judge had tested the evidence, certified a class or decided liability by October 7, 2019.

A trillion-dollar figure, with major caveats

The complaint said potential liability could exceed $1.4 trillion. That number was not a measured trading loss or an award. The pleading cited a fall in the combined market capitalization of all virtual currencies from roughly $795 billion on January 6, 2018, to $329 billion on February 6, 2018—a $466 billion difference—then pointed to possible trebling under antitrust and racketeering statutes. Three times $466 billion is $1.398 trillion, which explains the headline-scale estimate.

That calculation carried substantial limitations. Market capitalization is price multiplied by circulating supply, not cash that necessarily entered or left the market. A change in aggregate market value does not by itself establish causation, identify injured traders or prove recoverable damages. The complaint itself acknowledged that calculating damages at that stage was premature.

The pleading also alleged that Tether issued 2.8 billion USDT during 2017 and 2018 and used it to purchase other cryptocurrencies through Bitfinex. That figure and the claimed purpose of the issuance were plaintiffs’ assertions, not independently established facts on October 7.

Tether denied manipulation

Tether had published a preemptive response on October 5, 2019, saying it expected an imminent lawsuit based on an unpublished, non-peer-reviewed study. The company rejected the methodology it anticipated would underpin the case, said all Tether tokens were fully backed by reserves and maintained that issuance followed market demand rather than an effort to control crypto-asset prices.

The dispute arrived with institutional pressure already building. On April 25, 2019, the New York attorney general had announced an investigative court order and alleged that operators of Bitfinex and Tether concealed the apparent loss of $850 million in commingled client and corporate funds. That separate state investigation did not prove the federal plaintiffs’ broader market-manipulation theory, but it made questions about reserve quality, related-party transactions and exchange risk especially consequential.

USDT functioned as trading infrastructure: traders used the dollar-linked token to move value among venues and quote crypto pairs where direct banking access was limited. A challenge to its backing or issuance practices therefore reached beyond one issuer. It raised questions about whether a privately issued settlement asset could transmit counterparty and disclosure risk across multiple markets.

What October 7 established

The verifiable development was narrow but important: a federal complaint was in the public record, it made sweeping manipulation claims, and Tether denied them. The $1.4 trillion figure was advocacy built from a market-capitalization comparison and statutory multipliers. It was not a contemporaneous factual finding.

Later context

Later proceedings should not be read backward as facts known in 2019. In an opinion signed February 23, 2026 and entered publicly on March 6, 2026, the district court granted class certification with narrowed definitions. Certification allowed specified claims to proceed collectively; it did not decide that manipulation occurred or that the plaintiffs were entitled to damages.