UST’s collapse explained: how a broken LUNA mechanism wiped out $40B and cost Do Kwon $4.5B

The UST stablecoin collapse in May 2022 exposed vulnerabilities in Terra’s algorithmic model, as the token lost its dollar peg and the mechanism linking it to LUNA failed to restore stability.

The collapse erased tens of billions of dollars in market value and ultimately became the focus of a U.S. Securities and Exchange Commission enforcement case against Terraform Labs and its founder, Do Kwon. A federal jury later found the defendants liable for fraud, while the SEC announced a settlement exceeding $4.5 billion.

Unlike reserve-backed stablecoins that hold assets intended to support their value, the UST stablecoin was designed to maintain its $1 value through its relationship with LUNA. According to the SEC, UST was intended to remain pegged to the U.S. dollar through an algorithm that allowed it to be exchanged for LUNA.

When the mechanism failed under severe selling pressure, however, both assets plunged. The episode became one of the most consequential failures in the digital-asset market and raised broader questions about the ability of algorithmic stablecoins to maintain a stable value without conventional reserves.

UST stablecoin relied on LUNA rather than dollar reserves

The UST stablecoin was part of a wider ecosystem developed by Terraform Labs. At its peak, UST had a market value exceeding $17 billion, according to the SEC’s 2023 complaint. Its design was closely tied to LUNA, with the system relying on the relationship between the two tokens to maintain UST’s one-to-one peg with the U.S. dollar.

The structure created a fundamental dependency: confidence in UST was closely connected to confidence in LUNA. When UST began trading below $1, the system’s mint-and-burn mechanism increased the supply of LUNA as it attempted to restore the peg.

Instead, the falling value of LUNA intensified pressure on the wider Terra ecosystem.

The resulting feedback loop accelerated the decline of both assets. UST lost its intended stability while LUNA’s supply expanded and its price collapsed. The two-token structure could not absorb the scale of selling pressure that emerged in May 2022.

The SEC later said that UST and Terraform’s other tokens fell close to zero after UST depegged, contributing to losses for investors who had committed funds to the ecosystem.

SEC investigation put UST stablecoin at center of fraud case

The collapse also brought regulatory scrutiny of Terraform Labs and Kwon. In February 2023, the SEC charged the company and its founder with securities fraud and other violations, alleging that they misled investors about the stability of UST and other aspects of the Terra ecosystem.

The regulator argued that Terraform and Kwon had promoted UST as an algorithmic stablecoin capable of maintaining its dollar peg while allegedly misleading investors about how the system actually functioned.

In April 2024, a federal jury found Terraform Labs and Kwon liable for fraud following a nine-day trial. The SEC subsequently announced that Terraform and Kwon had agreed to pay more than $4.5 billion in disgorgement, interest and civil penalties.

“This case affirms what court after court has said: The economic realities of a product not the labels, the spin, or the hype determine whether it is a security under the securities laws,” — Gary Gensler, then SEC Chair.

The SEC said the collapse wiped out approximately $40 billion in market value almost overnight, affecting numerous investors, including retail participants.

Gurbir S. Grewal, then director of the SEC’s Division of Enforcement, described the consequences more directly following the jury verdict.

“Terraform Labs and Kwon, its former CEO, deceived investors about the stability of the crypto asset security and so-called algorithmic stablecoin Terra USD,” — Gurbir S. Grewal, then SEC Division of Enforcement director.

UST stablecoin collapse reshaped debate over algorithmic models

The failure of the UST stablecoin became a major example of the risks associated with algorithmic approaches to maintaining a digital asset’s value.

The core problem was not simply that UST experienced selling pressure. The design depended on the market continuing to place sufficient value on LUNA, the asset used to support the stabilization mechanism. Once confidence in the ecosystem deteriorated, the mechanism faced increasingly difficult conditions.

As UST moved away from its $1 target, attempts to restore the peg contributed to greater LUNA issuance. The resulting increase in supply added further pressure to LUNA’s market value, creating the death spiral described in the supplied account.

The SEC’s later proceedings also shed additional light on the circumstances surrounding UST’s stability. In December 2024, the regulator charged Tai Mo Shan, a subsidiary of Jump Crypto Holdings, with misleading investors about UST’s stability. The SEC said Tai Mo Shan had purchased more than $20 million worth of UST during an earlier depeg in May 2021 under an arrangement with Terraform, helping push the token back toward its $1 peg.

“This case reminds us that, too many times in the crypto markets, we’ve seen significant investor losses due to fraud,” — Gary Gensler, then SEC Chair.

The development added another layer to the regulatory history surrounding the UST stablecoin, showing that questions about its stability had emerged before the much larger May 2022 collapse.

UST stablecoin legacy remains relevant to crypto markets

The consequences of the UST stablecoin failure extended beyond Terraform Labs. The collapse became a reference point in discussions about stablecoin design, investor protection and the importance of mechanisms capable of supporting redemptions during periods of extreme market stress.

For crypto market participants, the episode demonstrated the distinction between a stablecoin’s stated objective and the mechanism actually responsible for maintaining its value. A token can target a $1 price without having conventional dollar reserves or other assets readily available to meet redemptions.

The Terra case also became significant from a regulatory perspective. The SEC’s litigation ultimately resulted in a jury verdict against Terraform Labs and Kwon, followed by a multibillion-dollar settlement and the winding down of Terraform’s operations.

The UST stablecoin collapse therefore remains an important case study in the relationship between crypto market structure, investor confidence and regulatory oversight. Its failure showed how quickly a system built around interconnected tokens can unravel when the underlying market confidence supporting the mechanism disappears.

As of September 23, 2026, the broader cryptocurrency market continues to contain a wide range of stablecoin and digital-asset models. Pluang’s market snapshot cited in the source story showed mixed performance among major cryptocurrencies, with 36 of 50 tracked assets rising and 13 falling at the time of its September 23 update.

That market data provides contemporary context, but the lessons from the UST stablecoin collapse remain rooted in the events of 2022 and the subsequent regulatory proceedings. The Terra episode continues to illustrate why the architecture behind a stablecoin can matter as much as its promise to maintain a stable price.