Fiat-Backed Stablecoins Explained: How USDT and USDC Maintain Stability

In a market where execution speed and capital safety define edge, fiat-backed stablecoins like USDT and USDC have become the backbone of global crypto liquidity. While both aim to maintain a $1 peg, their divergence in transparency, regulatory alignment, and market positioning creates distinct trade-offs for users. Understanding their typical mechanism and structural differences is critical for traders to deploy liquidity across both CeFi and DeFi environments. 

How fiat-backed stablecoins work

Understanding how fiat - backed stablecoins work requires looking at both the mechanisms that keep their price anchored and the systems that ensure sufficient reserves behind each token.

Pegging mechanism 

The mechanism behind fiat-backed stablecoins is the set of design rules and incentives used to keep a token’s price anchored (typically 1:1) to the US dollar. 

Here is the breakdown of the mechanism for you to hold a fiat-backed stablecoin.  

Step 1: Deposit (off-chain). You send $1 USD to the custodian bank of the issuer, for example Tether for USDT or Circle for USDC. This is a real fiat held in the banking system. 

Step 2: Confirmation. The issuer confirms receipt and records your entitlement to stablecoins.

Step 3: Minting (on-chain). The issuer mints 1 new stablecoin on a supported blockchain (Ethereum, Tron, etc). Total supply increases by 1.

Step 4: Distribution. The issuer transfers the newly minted stablecoin to your wallet address. At this point, you hold 1 USDT/USDC, while the issuer holds an equivalent amount of fiat reserves as 1 dollar backing the token. 

The peg is central to a stablecoin’s sustainability, as it represents its most essential defining feature. The key to a reliable peg is primarily built on two principles for any issuer:

• First, consistently upholding full or over-collateralized backing to reassure users that redemptions can always be honored.
• Second, structuring reserves, with a focus on liquidity and resilience, to prioritize the ability to meet large-scale redemptions over pursuing higher returns.

In the realm of crypto, stablecoins tend to have in common: robust reserves, reliable redemption, and efficient arbitrage. This shows a strong correlation between peg swings and the fiat reserve maintenance. 

Fiat-collateralized stablecoins commonly have their peg maintained through reserves: issuers hold cash or cash-equivalents and allow authorized participants to mint/redeem tokens at $1, or create arbitrage that pulls the market price back to par. 

Reserve maintenance  

For reserve-backed stablecoins, maintaining holders' trust hinges fundamentally on the quality and transparency of reserves. Issuers are required to provide regular attestations to assure the public that each token is fully backed. This transparency helps reduce information asymmetry and underpins holders’ trust.

However, transparency alone is not sufficient to guarantee stability. Market confidence is inherently fragile and highly reflexive, particularly during periods of financial stress. Even a well-collateralized stablecoin like USDC has experienced temporary depegging when external shocks such as banking sector risks undermine user sentiment.

In such scenarios, prices in secondary markets may deviate from the intended $1 peg, reflecting perceived counterparty and liquidity risks rather than actual reserve insufficiency. 

To counteract this, redemption arbitrage plays a critical role. It is the practice of exploiting price differences for the same asset across markets to earn risk-adjusted profit.

In crypto, traders might buy a stablecoin below $1 on one exchange and sell it closer to $1 elsewhere. This activity helps restore price equilibrium, especially for fiat-backed ones like USDT or USDC.

Let’s suppose USDT is priced at $0.98 on Exchange A, but $1.00 on Exchange B. A trader can do redemption arbitrage by buying 10,000 USDT on Exchange A for $9,800, and sell it for $10,000 in Exchange B. This could earn the traders a $200 profit. 

As more traders exploit this price difference, buying pressure on Exchange A pushes the price up while selling pressure on Exchange B pushes it down. Ultimately the prices in both the Exchanges are back toward $1. By continuously closing price gaps, arbitrageurs play a key role in maintaining market efficiency and, in the case of stablecoins, reinforcing their peg stability. 

What are the differences between USDT and USDC?

While both USDT and USDC lead the fiat-backed stablecoin market, each has its distinct value proposition, driven by underlying structural differences. 

Reserve composition 

From that reserve breakdown, you can extract important market implications for USDT and USDC holders. The portfolio of USDT reserve assets is most notable with the diversity which enables risk dispersion and flexibility for various types of crypto economic activities. 

Conversely, USDC holds its reserves entirely in cash and short-term U.S. Treasuries from traditional banks. While this empowers strong liquidity and security for holders, there are trade-offs. Since USDC’s reserve is over-dependent on stricter compliance, their holders may face US oversight and constraints in transactions. 

Stability 

The track record of USDC exhibits exceptional stability since its price ranged around ±$0.01 of its $1 peg. There are only a few times when USDC shrunk in confidence. In 2023, the Silicon Valley Bank crisis caused USDC to temporarily depeg to around $0.90. These reveal the major driver behind USDC’ reliability: its exposure to the U.S securities and banking system. 

Of the two stablecoins, USDC is more strictly regulated and compliant to U.S. regulatory frameworks, forming a strong correlation with the traditional fiat money system. Also, it maintains compliance with MiCA (European Union’s Markets in Crypto-Assets Regulation) and KYC (Know Your Customer) requirements. 

Until now, USDT traded very tightly around $0.998-1.002 intraday, yet tended to be more volatile in history, especially under turbulence. One of the largest depegs ever recorded of USDT is in Oct 2018 when it exposed early structural weaknesses. This led to the drop to $0.85 - 0.88, equal with the decrease of 12% on some exchanges.   

Transparency

Transparency over the reserves backing remains a key issue for traders to consider about stablecoins. USDT showed inferiority compared to USDC. In 2021, its issuer Tether has faced criticism for opaque reserve practices, leading to a $41 million fine from the US Commodity Futures Trading Commission. 

From the beginning, this has been essential to the USDC’s claims of verifiable reserves as a way to earn market acceptance. Every month, Deloitte - one of the Big Four audit firms independently reviews and verifies the reserve composition. After that, these documents are released to the public, ensuring disclosure. 

Before, USDT relied on quarterly assurance reports by BDO Italia whose reports have limited assurance. Lately, Tether - the issuer of USDT announced that they have selected a Big Four audit firm to conduct the first full financial statement audit. This demonstrates their commitment to transparency about reserve infrastructure, hence strengthens the position of USDT in the market. 

Network adoption and blockchains support

With a market capitalization of $184.05B, USD Tether commands more than double the size of USD Coin at $78.51B, reinforcing its entrenched dominance as the primary liquidity layer in crypto markets. Additionally, USDT is deeply embedded across global exchanges, especially in emerging markets where access to USD banking rails is limited. 

Surprisingly, this lead fades when considering the infrastructure reach of two dollar-collateralized stablecoins. USDC spans 72 blockchain networks, while USDT has 54. 

Use case focus

The graph showcases USDT vs USDC daily trading volume, USD millions, 30-day moving average from 2018 to 2025. It is clearly seen that USDC is traded far less and consistently remains under 20,000 USD millions. This creates a huge gap behind USDT whose trading volume fluctuates, yet having peaked up to nearly 180,000 USD millions. 

While USDC is often associated with lower trading volume and USDT with broader liquidity exposure, their differences are better understood through infrastructure and market positioning rather than simplified labels. In terms of value proposition, USDT excels in scale and operational flexibility; whereas USDC is well-known with its credibility and auditability. 

These enable each of the two stablecoins to thrive in varied use cases:

• USDC values regulation compliance, transparency, and government protection. That explains why it is typically preferred in regulated settings, particularly for B2B payments, payroll operations, and treasury management.
• USDT prioritizes liquidity, accessibility, and global reach. With fewer regulatory constraints, it is more widely utilized across decentralized exchanges and derivatives markets.

Overview of USDT and USDC

This table below compares differences between USDT and USDC across core features. 

In summary, USDT dominates in scale and liquidity, making it ideal for trading environments. Meanwhile, USDC stands out for transparency, regulatory alignment, and reserve quality, favoring institutional activities use cases.

Market indications of fiat-backed stablecoins

Market signals around fiat-backed stablecoins are increasingly shaped by two defining forces: the enduring dominance of the United States dollar and the accelerating wave of global regulatory frameworks.

The continuing dollar dominance 

Although having lost some grounds to digital currency, the United States dollar continues to anchor the global financial system. As a leading reserve currency, it accounts for around 60% of global reserves. Reported from BestBrookers in 2025, in terms of foreign exchange transactions and export invoicing, the U.S dollar took dominance with shares of 88% and 54%, respectively. 

This structural dominance is reinforced by the depth and liquidity of U.S. Treasuries, which remain the world’s primary reserve asset and collateral benchmark. 

As a result, global reliance on the U.S. dollar is not merely cyclical but structural, making any near-term currency displacement highly unlikely. 

Undoubtedly, dollar-pegged types take the vast majority in the stablecoins’ circulation supply. Consequently, the enduring global demand for USD directly reinforces the acceptance and expansion of dollar-backed stablecoins across both emerging and developed markets. Their adoption is particularly evident in economies experiencing currency instability or capital controls, such as Argentina, Turkey, and Nigeria. 

To them, USD-backed stablecoins are used as a store of value and medium of exchange. This trend reflects a form of digital dollarization, where demand for the dollar persists through blockchain-based channels. 

Regulations of stablecoin

Given their direct linkage between USD-pegged stablecoin to the traditional financial system, their maturation remains closely tied to the US establishment of unified regulatory frameworks. This alignment is crucial for narrowing regulatory gaps across stablecoins and ensuring their resilience during periods of market stress. 

This evolution was notably marked by the introduction of the GENIUS Act (Guiding and Establishing National Innovation for U.S. Stablecoins Act) in late July 2025. A central provision of the Act mandates that stablecoins be fully backed on a 1:1 basis by short-term, highly liquid assets, primarily U.S. Treasuries. Issuers are required to maintain complete reserve backing with liquid assets such as cash or short-term government securities, alongside providing monthly disclosures detailing the composition of those reserves.

The GENIUS Act has already delivered significant momentum to the stablecoin sector: daily transaction volumes have followed a sharp “hockey stick” growth trajectory, rising from approximately $1 trillion prior to the Act to $4 trillion after its enactment.

Even USDT is currently not regulated, but will be regulated by the GENIUS Act of the U.S. after it takes effect. 

Beyond U.S. government regulations, other dynamic financial hubs have adopted  assertive measures. For instance, major EU-regulated platforms have either delisted Tether or restricted it to “sell-only” status due to non-compliance with the MiCA framework.

The bottom line

Fiat-backed stablecoins are essentially financial instruments shaped by issuer behavior, reserve quality, and market trust. It is no surprise when two dominating stablecoins are both pegged to the dollar: USDT and USDC. This is reinforced by the U.S. dollar's dominance across global crypto liquidity, without any foreseen near-term displacement. 

Sources

• USDT vs USDC: Making the Right Choice for Stability and Liquidity https://www.slash.com/blog/usdt-vs-usdc 
• Demystifying Stablecoins: The use cases, the pegging mechanism, and the implications on financial market https://privatebank.jpmorgan.com/apac/en/insights/markets-and-investing/demystifying-stablecoins 
• A Guide To Stablecoins: Majority Fiat-Backed Stablecoins - USDT, USDC, PYUSD: https://seekingalpha.com/article/4884816-guide-to-stablecoins-majority-fiat-backed-stablecoins-usdt-usdc-pyusd 
• How Stablecoins Could Get More Stability With the GENIUS Act: https://knowledge.wharton.upenn.edu/article/how-stablecoins-could-get-more-stability-with-the-genius-act/