USDC is a dollar stablecoin issued by Circle Internet Group, a company listed on the New York Stock Exchange since its June 2025 initial public offering (prospectus filed with the SEC on June 5, 2025), redeemable one to one for US dollars and backed by a reserve of cash and short-dated US government securities that an independent accounting firm examines every month. On September 17, 2026 there were about 73.7 billion USDC in circulation across 39 blockchain networks, according to Circle's own issuance data.
For a payments team the relevant facts are narrower than the marketing: what exactly sits in the reserve, who can redeem, which networks carry meaningful liquidity, and what a payout in USDC costs and takes on the way to a bank account in São Paulo or Mexico City. This post covers those four and ends with the cases where USDC is not the right instrument. If the concept of a stablecoin is new, start with what a stablecoin is and come back.
What sits in the reserve
Circle's transparency page, as of its September 14, 2026 update, describes the USDC reserve in three buckets: cash held at banks, deposits at systemically important financial institutions, and the Circle Reserve Fund, an SEC-registered government money market fund managed by BlackRock under ticker USDXX. The fund holds cash, US Treasury bills with short maturities and overnight reverse repurchase agreements collateralized by Treasuries. Circle states that the reserve is held for the benefit of USDC holders and is segregated from Circle's own assets.
Two features of this structure matter to a treasurer. The first is duration: the assets mature in days to weeks, so the reserve does not carry the interest-rate risk that sank Silicon Valley Bank in March 2023, when USDC itself traded below par for a weekend because 3.3 billion dollars of its cash was at that bank (Circle press release, "$3.3 Billion of USDC Reserve Risk Removed, Dollar De-peg Closes", March 12, 2023). The second is disclosure: the fund's holdings are visible on BlackRock's site, not only in Circle's summary.
The reserve is examined monthly by Deloitte & Touche LLP under AICPA attestation standards; the reports are published on circle.com/transparency, and on September 17, 2026 the latest available covered July 2026. An attestation is not a full audit of the company (Deloitte also audits Circle's annual financials), but for a reserve the monthly examination is the document that answers the only question that matters: were there more dollars of reserve than tokens in circulation on the report date.
How much USDC exists and where it lives
Circle's public issuance API reported the following on September 17, 2026:
USDC in circulation by network, Circle issuance data, September 17, 2026, rounded.
Network | USDC outstanding |
Ethereum | 50.0 billion |
Solana | 6.5 billion |
Base | 4.3 billion |
Arbitrum | 2.6 billion |
Stellar | 0.31 billion |
Tron | 0.03 billion |
All 39 networks | 73.7 billion |
The distribution tells a payments operator two things. Ethereum still holds two thirds of the supply, so the deepest liquidity for large redemptions and OTC trades is there, at the highest transaction fees. Base, and to a lesser extent Polygon (0.6 billion on the same date), carry a growing share of payment traffic because fees are cents rather than dollars. Tron, the network where USDT, covered in its own explainer, dominates in Latin America, holds almost no USDC, and that asymmetry decides token choice in some corridors. Circle announced on February 21, 2024 that it was discontinuing support for USDC on Tron, with transfers off the network supported through February 2025, which explains the residual balance.
For context on the overall market, DefiLlama's stablecoin tracker put USDC at 28 percent of dollar stablecoin supply on September 17, 2026, second to USDT.
Who can redeem, and what that means for the peg
Circle redeems USDC for dollars at par for its direct customers, which are businesses that pass onboarding: exchanges, payment providers, fintechs, treasuries. Everyone else redeems indirectly, by selling USDC on an exchange or through a provider that has a Circle account. This two-tier structure is normal for fiat-backed stablecoins, and it works as long as the first tier is large and active, because their arbitrage pins the market price to par.
It also explains the March 2023 episode. The discount opened over a weekend, when banks were closed and no direct redemption could clear, and closed on Monday morning as redemptions resumed. The lesson for an operator is not that USDC is unsafe; it is that a stablecoin's peg is only as liquid as the banking hours of its issuer. A treasury that must convert on a Saturday should already hold the local currency, or use a provider whose fiat rail runs 24/7, like Pix (Brazil's instant payment system, run by the Central Bank).
Where USDC fits in a Latin American payment flow
The common flows we see run in three directions.
Into the region. A US or European company holds USDC and pays suppliers, contractors or sellers in Brazil or Mexico. The provider quotes a rate, receives USDC on a supported network, and pays out in reais or pesos over the local rail. Our USDC to BRL corridor page and USDC to MXN corridor page show the live rate and the pairs available per network.
Out of the region. A Brazilian exporter or a Mexican marketplace collects locally and converts to USDC to hold dollar value or to pay a counterparty abroad. This is the treasury use, and the thing being bought is not yield but the ability to hold dollars and move them at any hour without opening a US bank account.
Across the region. A Colombian platform pays Argentine contractors, or a Mexican fintech settles with a Brazilian partner. Here USDC is the bridge asset between two local currencies, and the alternative is two SWIFT legs through New York.
In each case USDC is the settlement layer, not the product. The end customer sees pesos or reais arrive.
When USDC is not the right token
Corridors where the counterparty holds USDT on Tron. Much of the retail and OTC liquidity in Argentina, Colombia and parts of Mexico runs on USDT over Tron, where USDC is thin. Forcing USDC into that leg adds a conversion. Let the destination decide.
Payments that need to be reversible. Like every stablecoin transfer, a USDC transfer is final. A refund is a new payment.
Domestic flows. A Brazilian company paying a Brazilian company should use Pix; a Mexican one should use SPEI (Mexico's interbank transfer system, run by Banxico). USDC in the middle would add a spread and a counterparty for no gain.
Treasuries that cannot tolerate any weekend gap. The March 2023 discount lasted about two days and recovered fully. A treasury that would have been forced to sell during those two days should hold part of its balance in the local currency it will need.
What a USDC payout looks like on Lumx
Lumx is stablecoin payments infrastructure for businesses that move money between Latin America and the rest of the world: one API to collect, hold, convert, and pay out in BRL, MXN, COP, USD, EUR, and GBP or in USDC and USDT, over local rails such as PIX, SPEI, PSE, ACH, FEDWIRE, SEPA, and Faster Payments, with SWIFT and on-behalf-of payments and collections (POBO and COBO) in USD, EUR, and GBP, plus named virtual accounts, custodial wallets, and KYB/KYC built in.
For USDC specifically, we accept and pay out on Ethereum, Polygon and Base against reais, dollars and pesos, and on Stellar for reais on-ramp; the current pair list per network is on the coverage page and the corridor pages linked above. A client sends USDC to its custodial wallet or receives it when a customer's named virtual account deposit auto-converts, requests a quote against BRL or MXN, and gets the payout over Pix or SPEI, normally within minutes of the blockchain confirmation. Every state change arrives by webhook, including a compliance hold with its reason and a bank rejection with the rail's return code.
I made the network decision the hard way. Early on we supported USDC on Ethereum only, because that is where the liquidity was, and watched a client's payroll run pay more in network fees than in FX spread on a month when Ethereum was congested. We added Polygon within weeks and later Base. The rule I took from it: the network is a cost line the client will see on the invoice, so it is our job to route to the cheapest one that has the liquidity, not the client's job to know the difference.
Methodology and sources
Circulation and per-network figures come from Circle's public issuance API (api.circle.com/v1/stablecoins) queried on September 17, 2026, rounded to one decimal. Reserve composition and the attestation schedule come from circle.com/transparency, which showed a reserve update dated September 14, 2026 and monthly Deloitte & Touche examination reports through July 2026. Market share is from DefiLlama's stablecoin page on the same date. The March 2023 depeg follows Circle's press release of March 12, 2023 linked above; the Tron decision follows Circle's blog post of February 21, 2024; the IPO date follows Circle's prospectus filed with the SEC on June 5, 2025 (EDGAR, CIK 1876042). Figures marked with a date change monthly; the stablecoin glossary has stable definitions.
Verified on September 17, 2026. Operational context, not legal, tax, or investment advice.
Cover photo: Rafael Garcin on Unsplash.
Who issues USDC?
Circle Internet Group, a US company listed on the New York Stock Exchange since June 2025. Circle mints USDC when a direct customer deposits dollars and burns it when a customer redeems. The reserve is held at banks and in the Circle Reserve Fund managed by BlackRock.
Is USDC audited?
The reserve is examined every month by Deloitte & Touche LLP under AICPA attestation standards, and the reports are public on Circle's transparency page. Circle's corporate financial statements are separately audited by Deloitte.
Which networks should a business use for USDC payments?
Ethereum for the deepest liquidity and largest amounts, Polygon or Base for lower fees on frequent payouts. Lumx routes to the network with the best cost for the pair; the client does not have to choose.
Can USDC lose its value?
It has traded below one dollar for short periods, most notably over the weekend of March 11 and 12, 2023, when 3.3 billion dollars of its reserve cash was at Silicon Valley Bank, and it recovered as redemptions reopened on the Monday. The reserve is designed so the token can always be redeemed at par when banks are open.
