Why these three, and why now
If you already trust USDC and USDT, this comparison is largely academic. You hold a dollar, you collect T-bill yield, you move on. The reason advanced DeFi users keep looking at Sky, Ethena, and Frax is that they each try to solve a different problem USDC cannot solve at all: a dollar that does not rely on a bank account, a regulator's goodwill, or a centralized freeze button.
Sky (the rebrand of MakerDAO) pursues that goal by overcollateralizing crypto deposits. Ethena pursues it with a synthetic dollar backed by short perpetual futures positions. Frax spent years chasing a hybrid model that lived somewhere between the two. None of these is a free lunch. The yield on each protocol is the market's compensation for a specific, identifiable failure mode, and naming that failure mode is the entire point of this article.
Because the failure modes are different, the protocols actually compete for different risk budgets. A user who can tolerate an ETH liquidation cascade but cannot stomach basis-trade unwind tends to lean toward Sky. A user who is comfortable reading funding-rate charts and is wary of bank-fiat risk tends to look at Ethena. A user who remembers Terra often avoids Frax entirely, even though Frax has changed significantly since the 2022 collapse of UST. Treat this comparison as a tour of three different theories of decentralized money, not a ranking.
How Sky MakerDAO builds a dollar
Sky is the consumer-facing brand that absorbed MakerDAO in 2024. The core mechanism is unchanged and goes back to 2017: you lock crypto collateral into a smart contract vault, you borrow a dollar-denominated stablecoin against it, and because the collateral is volatile, the contract requires you to post more value than you borrow. That ratio is the collateralization ratio, and on the standard ETH vault it sits around 150% to 173%, depending on the risk tier of the asset.
The borrowed token used to be DAI. After the rebrand, new issuance is dominated by USDS, with DAI migrating on a one-to-one basis. The dollar stays soft-pegged through arbitrage: if USDS trades below $1 on exchanges, traders buy the cheap token and pay down their debt, removing supply and pushing the price back up. If USDS trades above $1, users mint more, sell it, and the supply expansion pulls the price back down. The peg is enforced entirely by code and the open market, with no human deciding who gets a USDS account.
The yield that lenders see on the Sky Savings Rate is paid in SKY (the new governance token), and that yield is essentially the market price users are willing to pay for censorship-resistant borrowing. Real-world assets, including U.S. Treasuries and tokenized loans through partners like Coinbase and Centrifuge, sit in the backing pool alongside the crypto collateral. The diversification is real: it is what allows Sky to advertise yield that looks competitive with T-bill returns, while keeping the system fully on-chain.
How Ethena builds a dollar
Ethena's USDe is a synthetic dollar, which means there is no vault, no borrowed position, and no overcollateralization in the Sky sense. Instead, USDe is minted when a user deposits eligible collateral (currently BTC, ETH, and a short list of liquid tokens) and Ethena opens an equivalent short perpetual futures position on a centralized exchange. The protocol is delta-neutral on paper: your long crypto is offset by the short futures, so the size of your position should not move with BTC or ETH price.
The yield comes from perpetual swap funding, which is the fee that long traders pay short traders every eight hours when the perp trades above the spot index. In bullish markets the funding rate is usually positive, often meaningfully so, and that stream accrues to the USDe backing pool. USDe was launched in early 2024 and grew through one of the most aggressive adoption curves any stablecoin has had, crossing several billion in supply within months.
The mechanism has one assumption that everything else depends on: funding rates must, on average, stay positive. They usually do in bull markets, but they have a long history of going sharply negative in choppy or bear conditions, when short traders are the ones paying longs. When funding flips, USDe stops earning and starts bleeding, and the protocol has to absorb the cost out of its reserves or let USDe's value drift below $1.
How Frax builds a dollar
Frax is the oldest of the three designs and the one that has changed the most. In its original form, launched in 2020, FRAX was a hybrid: a fraction of every dollar was backed by real collateral, and the rest was backed by a seigniorage share token (FXS) that holders were expected to burn to absorb redemptions during a peg crisis. The model resembled the design that Terra's UST was running, which is why a lot of serious DeFi users walked away from FRAX in May 2022.
Frax did not collapse. The team voluntarily de-algorithmicized in 2023, migrating FRAX to fully backed USDC collateral and launching a separate, distinctly governed stablecoin called frxUSD that runs on the Frax v3 framework with a stable peg and a yield-bearing sibling called sfrxUSD. FXS still exists, and the partial-algorithmic framing has not been fully erased from old documentation, so the brand carries the scar even if the mechanism no longer deserves it.
The honest read is that Frax survived by becoming closer to what USDC already is. That decision cost it a lot of ideological community in 2023, but it kept the protocol alive and gave it a credible path to compete on Treasury yield and RWA distribution. The current Frax product is closer to Sky's RWA strategy than to Terra's algorithmic design.
The real risks, mechanism by mechanism
This is where the comparison earns its keep. All three protocols show plausible-looking yields, all three have audit firms and dashboards, and all three can be marketed in ways that hide the bad day. Three failure paths matter most.
For Sky: collateral liquidation in a fast crash. The system depends on vaults being worth more than the debt they issued. In a fast depeg or a 30% intraday move, liquidators have to step in to repay debt and reclaim collateral. In March 2020, when ETH crashed and centralized exchanges froze, the old Maker system accumulated millions in unbacked DAI. The current system is bigger, more diversified, and includes real-world assets, but a coordinated liquidity crisis could still leave vaults that cannot be liquidated cleanly.
For Ethena: the basis trade unwinds and the insurance fund question. If perp funding turns deeply negative for weeks, the protocol must pay longs out of its insurance fund. That fund held a meaningful sum early on, but Ethena's reporting on its size, custody, and counterparty risk has changed several times. Critics have pointed out that the fund is, in practice, just an off-chain balance sheet entry, while supporters argue that the centralized exchange custody is the only way to clear billions in derivatives at all. Both can be true. The point is that the safety net is human-managed.
For Frax: peg-credibility tail risk. The current Frax is fully collateralized, but the brand still carries the algorithmic era. In a market-wide flight to quality, traders and desks sometimes sell anything that does not have the cleanest possible reputation, and FRAX is occasionally caught in that flow. Liquidity in FRAX can also be thinner than in USDC, so a single large seller can move the price on a single venue.
Regulatory pressure on synthetic dollars
Synthetic stablecoins sit in a different regulatory bucket than fully reserved ones, and that gap is now visible. The U.S. Treasury, the SEC, and the CFTC have all, at various points, flagged that tokens whose value depends on derivatives positions may be treated as derivatives, securities, or commodities depending on how they are marketed and structured. Senator Cynthia Lummiss's draft bill in 2023, and the follow-up proposals from the Trump administration's 2025 Working Group on Digital Asset Markets, have both drawn lines around synthetic dollars in particular.
Sky is partially exposed because its RWA leg includes tokenized Treasuries and loan positions that touch U.S. financial intermediaries. Ethena is the most exposed of the three, because the basis trade requires centralized exchanges as counterparties, and offshore exchanges may restrict U.S. users or face enforcement actions that close the funding stream. Frax's regulatory risk is more about its banking and custodian relationships than about its on-chain mechanism.
The practical effect today is geographic. U.S. retail users have effectively been locked out of the direct USDe minting interface. The protocol continues to run, but the pool of eligible users is narrower than the marketing implies. Any user outside the United States should still assume the same constraints can land in their jurisdiction on short notice.
What it looks like to actually use each one
If you hold ETH and want a dollar you can borrow against without selling, Sky is the most natural fit. You deposit ETH, you mint USDS, you pay a stability fee, and you can deploy the USDS into a yield-bearing position or use it as collateral elsewhere. The tax treatment is generally simple: you borrowed, you did not sell. The downside is liquidation risk if ETH drops hard, and you need to monitor your health factor manually.
If you are bullish on crypto funding rates and want a leveraged bet on that without picking individual long positions, Ethena can be more efficient. You mint USDe with BTC or ETH, Ethena opens the hedge, you hold a token designed to stay at $1 while accruing the funding. The risk is asymmetric: funding flips negative, and your dollar-peg token either drifts below $1 or the yield turns into a slow bleed funded by the insurance fund.
If you want exposure to a tokenized Treasury strategy with a smaller, more experimental protocol, frxUSD is the newest option on the Frax stack. The credit and custody story is shorter than Sky's, the integrations are less battle-tested, and the yield is competitive without being exceptional. For most users, the honest summary is that frxUSD is a fringe RWA play, not a core stablecoin position.
How to follow decentralized dollar news the smart way
Stablecoin issuers move fast and so does the news around them. Funding rates flip, RWA partners get sanctioned, governance proposals ship on weekends. Tracking all three protocols manually across X, Discord, forum threads, and dashboards is a losing game. Zippfeed aggregates Sky, Ethena, and Frax headlines with sentiment scoring (bullish, neutral, or bearish) and an importance rating, so you can see which stories actually move positioning and which ones are noise.
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