Yearn Finance - Strategy Architecture
Strategies are the engine rooms of Yearn's yVaults. Each strategy is a separate smart contract that knows how to deploy your capital into a specific DeFi protocol - and crucially, how to get it back. Learn how Yearn's keeper rotates capital between strategies, how risk is scored, and why strategy architecture determines everything about vault returns and depositor risk.
Capital Flow: How Yearn Rotates Capital Between Protocols
Yearn's keeper monitors yield across all approved strategies and rotates capital to the highest risk-adjusted return. The diagram below shows how capital flows through a typical multi-strategy vault. Arrows show fund movement; percentages indicate approximate allocation.
$50M TVL
monitors APY
? Strategy Risk Scoring - Interactive Explorer
Yearn scores each strategy from 1 (conservative) to 5 (speculative) across four dimensions: TVL correlation (does the strategy move with the market?), complexity (how many steps can fail?), counterparty risk (which protocols does it depend on?), and smart-contract risk (audit coverage, age, usage). Drag the slider to explore how these dimensions shift across risk bands.
Vault APY Comparison - Across Strategy Types
Not all vaults are created equal. Stablecoin vaults are the safest but offer the lowest yield. LP vaults on Curve/Uniswap offer the highest APY but expose depositors to impermanent loss and protocol depeg risk. ETH staking vaults sacrifice some yield for ETH price exposure.
Strategy Formulas - The Math Behind the Yields
r = periodic rate (decimal)
n = compounding frequency
e.g. 5% monthly rate:
APY = (1 + 0.05/12)12 ? 1
= 5.12% APY
rnet = rgross (1 ? feemgmt) ? feeperf max(0, gain)
Example: 8% gross, 2% mgmt, 20% perf:
net = 0.08 0.98 ? 0.2 0.06 = 6.64%
dimi ? [0,1] per dimension
wtvl=0.35, wcomplex=0.35
wcounterparty=0.15, wsc=0.15
Band = round(Riskcomposite 5)
Only charged on profits above high-water mark (HWM)
HWM updates after each harvest if SPcurrent > SPHWM
Protects depositors from fee on un-realized gains
How strategy architecture works
Each Yearn vault delegates capital management to one or more strategy contracts. A strategy knows
three things: how to deploy an asset into a target protocol, how to monitor its position, and how
to unwind and return the asset when the keeper calls for withdrawal. Strategies are written in
Solidity and inherit from Yearn's BaseStrategy contract, which standardizes the
harvest(), withdraw(), and liquidate() interfaces that every
vault expects.
The critical innovation in Yearn's architecture is the separation between the vault (which handles
deposit/withdrawal accounting and yvToken minting) and the strategy (which handles the actual
yield generation). This means the same vault contract can swap strategies without depositors
needing to take any action. The keeper monitors all active strategies and calls
harvest() on the best performer when gas is cheap and profit exceeds the cost of
execution - typically when a strategy has accumulated more than ~$1,000 in profit.
Yearn's strategy registry is open - anyone can submit a strategy for review. The Yearn risk team then evaluates it on-chain (TVL limits, emergency shutdown behavior, rug-pull potential) and off-chain (team reputation, code audit history, protocol governance risk). Approved strategies receive a TVL cap initially and can be gradually increased if performance is consistent.
Key concepts
- Strategy debt
- Each strategy has a "debt" figure representing how much capital the vault has allocated to it. The sum of all strategy debts equals total vault TVL. When a strategy is migrated or withdrawn, its debt is returned to the vault. Debt is tracked in the vault's asset units so a USDC vault's strategy debt is always expressed in USDC, not strategy-specific tokens. This makes the vault's accounting clean and allows depositors to calculate their share of each strategy's P&L.
- Harvest cycle
- A harvest consists of: (1) the strategy calling
report()on the vault with its realized profit; (2) the vault computing the performance fee in yvToken shares and minting them to Yearn's treasury; (3) the remaining profit being added to the vault's total assets, which raises the share price. Yearn's keepers trigger harvests when estimated profit exceeds gas cost by 5 or more, usually 1-4 times daily for major vaults. - Strategy migration
- When Yearn wants to upgrade a strategy (bug fix, new logic) without interrupting the vault, it uses a two-step migration: the old strategy is first set to "arm" mode (no new capital allocated but existing positions remain), the new strategy is deployed and tested with small capital, then remaining funds are moved via the vault's
migrateStrategy()call. During migration, depositors can still withdraw normally. - Health check
- Yearn's keeper runs a health check before every harvest - a set of on-chain validations that verify the strategy's reported profit is within expected bounds. If a strategy reports an implausibly high profit (e.g., 1,000% in a day) or shows a loss exceeding a threshold, the keeper skips the harvest and alerts the Yearn risk team. This prevents a single bad strategy from corrupting the vault's share price.
- Total Value Locked (TVL) correlation
- A risk dimension that measures how much a strategy's performance correlates with the broader crypto market. A strategy that performs poorly in a bear market (e.g., long ETH in a downturn) scores high on TVL correlation and gets a higher risk weight. Low TVL correlation strategies maintain yield even in downturns because their yield source isn't tied to crypto prices.
- Slippage tolerance
- When strategies interact with AMMs (Curve, Uniswap) they specify slippage tolerance - the maximum price movement they'll accept before canceling the swap. Yearn typically sets 0.5-1% slippage tolerance for large trades. Higher slippage means more potential loss to MEV sandwich attacks; lower slippage means trades may fail in volatile conditions.
Why strategy architecture matters
Strategy architecture determines roughly 90% of a vault's risk-adjusted return profile. A poorly designed strategy may generate high APY in backtests but fail under real conditions - either through governance changes in the target protocol, liquidity crunches during market stress, or unanticipated interaction effects between multiple strategies in the same vault. Yearn's advantage is its deep institutional knowledge of how strategies behave across different market conditions, accumulated from running strategies since 2020.
The 2022 Terra collapse illustrated the importance of strategy risk scoring. Yearn had exposure to UST through several strategies, but its multi-strategy architecture and risk scoring system meant no single vault was catastrophically exposed. By contrast, protocols that had concentrated UST positions in single-strategy vaults suffered total loss. Yearn's post-Terra response - immediately freezing UST withdrawals and winding down positions in an orderly sequence - validated its emergency shutdown architecture.
For yield farmers evaluating Yearn vs. competitors (Convex, Beefy, Autofarm), the key differentiator is Yearn's keeper infrastructure. Yearn's keeper is one of the most sophisticated on-chain agents - it bundles transactions, uses flashbots for MEV protection, and optimizes for gas efficiency across 9 chains simultaneously. This operational edge translates to more frequent harvests, lower execution slippage, and ultimately higher net APY for depositors.
Frequently asked questions
- How does Yearn decide which strategy to allocate capital to?
- Yearn's keeper system uses a multi-factor ranking: current APY, estimated gas cost to execute, risk score, and correlation with existing vault positions. Strategies are ranked by risk-adjusted expected return - not raw APY. A strategy earning 20% APY with a complexity score of 5 and high smart-contract risk may rank below a 6% APY stablecoin lending strategy once you factor in the probability-weighted loss scenario. The keeper bot reallocates capital between strategies when the ranking changes significantly, typically a few times per day.
- What is the difference between a single-strategy vault and a multi-strategy vault?
- A single-strategy vault deploys all capital into one strategy - used when Yearn has high conviction in a specific deployment and wants minimal capital fragmentation. Multi-strategy vaults (the default for most Yearn vaults) distribute capital across ranked strategies - typically a conservative primary strategy holding 40-60% of capital and two or three higher-yielding secondary strategies. This means if the primary strategy suffers a loss, the vault's share price impact is cushioned by the other strategies. Yearn's newer V3 vaults all use the multi-strategy model.
- How does Yearn calculate performance fees and what is the high-water mark?
- Yearn charges a 20% performance fee on net profits above the high-water mark - the highest historical share price the vault has ever reached. If a strategy loses money, the share price drops below the high-water mark and no performance fee is taken until the vault recovers to the previous high. The 20% is calculated on realized profits only (when strategies harvest), not on paper gains. The management fee is 2% annually on deposited assets, calculated daily and taken in shares rather than from realized profit. For a depositor with $10,000 earning 8% gross APY: after ~$600 gross profit, the performance fee takes ~$120 (20% of profit above high-water mark), leaving ~$480 net annual profit.
- What are the main categories of Yearn strategies?
- Yearn strategies fall into five main categories: (1) Lending strategies - supplying assets to Aave, Compound, or dYdX to earn variable lending interest; (2) LP/stabling strategies - providing liquidity to Curve stablecoin pools or Uniswap V2/V3 ETH pairs to earn trading fees plus token incentives; (3) Liquid staking strategies - depositing ETH or wBTC into Lido, Rocket Pool, or staked derivatives to earn staking yield; (4) Leverage strategies - using Yearn's yvToken as collateral to borrow, re-deposit, and amplify yield (higher risk, higher reward); (5) Delta-neutral strategies - combining long and short positions to capture funding rates or basis spreads while maintaining near-zero directional exposure.
- How does Yearn's keeperbot avoid MEV and sandwich attacks when executing strategy transactions?
- Yearn's keeper infrastructure uses flashbots Protect and custom RPC routing to submit transactions directly to block builders without going through the public mempool. This prevents strategies from being front-run when adjusting???? or rebalancing LP positions. For higher-value transactions, keepers use bundle submission with co-processor pricing to ensure the transaction lands in the intended block at the expected gas price. Yearn's keeper is one of the largest private transaction senders on Ethereum, which gives it negotiating leverage with block builders for preferential ordering.
- What happens to strategy positions during an emergency withdrawal?
- When Yearn's multisig or governance triggers emergency withdrawal, three things happen in sequence: (1) new deposits are permanently halted; (2) the keeper begins unwinding strategy positions in order of liquidity - easiest positions (lending supply) are exited first, LP positions require the most time since they may need to withdraw from Curve or Uniswap pools; (3) withdrawal queue processes on a pro-rata basis once sufficient liquidity returns to the vault. In practice, Aave lending positions can be unwound in a single transaction, while a Curve 3pool LP position requires two transactions (remove_liquidity + remove_liquidity_one_coin). Depositors should expect 1-48 hours depending on strategy complexity and current gas conditions.