Stablecoin supply review: modest market growth hides diverging issuer trends

DefiLlama showed $307.134B of stablecoins, up $1.378B over seven days. USDT ($184.2B) and USDC ($73.8B) make up about 84% of it. A market this concentrated can grow while exposure to two issuers' operations and redemption processes stays just as concentrated.

The labels also hide different designs. USDT and USDC are fiat-backed. USDS is Sky's stablecoin, backed by a mix of crypto and real-world assets. USDe is Ethena's synthetic dollar, backed by hedged crypto positions. Calling them all "stablecoins" doesn't make their reserves equivalent.

USDS grew 3.01% this week, about 13× USDT's 0.23%. But on a $6.9B base that's roughly +$0.20B, while USDT's small rate on $184B added about +$0.42B. USDC fell about $0.31B. A large percentage on a small balance can contribute fewer dollars than a small percentage on a large one.

Add up the four named coins and they explain only about $0.33B of the week's $1.378B rise. The other ~$1.05B came from everything else, about 12% of supply growing roughly 2.9% in a week. That's a residual from rounded figures, but it's a clear lead: the headline growth this week mostly happened outside the coins people usually quote.

If a coin grew at a steady pace, the last 7 days would account for about 23% of its 30-day change. USDe's last week accounts for about 3%: it grew 11.26% over the month and just 0.32% this week, so nearly all of the surge happened earlier. USDS runs the other way: about 81% of its monthly gain came in the last week. USDT and USDC both did about half their monthly move in the last seven days.

That shows the pace differs across windows. It doesn't show why. A promotion, a change in demand for collateral, or broader positioning would each need independent evidence.

A useful stablecoin review asks how much dollar liquidity exists, which issuers dominate it, and where it is held or used. Market cap partly answers the first two. It says nothing about whether balances sit on exchanges, in lending pools or in wallets nobody touches.

Market-cap changes can also come from valuation effects, coverage updates and minting or redemption. They don't prove cash entered crypto trading. Reserve adequacy, redeemability and how fast the coins actually circulate all need separate evidence.

The stablecoin market grew slightly this week, but its two biggest issuers moved in opposite directions, the smaller ones moved at very different speeds, and most of the growth came from outside the names people quote. Reading the total alone would miss all of that.

The next step is the part market cap can't show: where these balances sit and what they do. That turns supply into a capital story that can be checked.