Why Vault APYs Differ From Realized Returns: Case Studies

By Chanuka Geekiyanage Oct 09, 2026

A DeFi vault advertising 12% APY does not guarantee that your deposit will earn 12% over a year. Actual returns depend on changing lending rates, token incentives, fees, asset prices, and withdrawal costs. Understanding these differences helps you compare vaults by their realized performance rather than headline yields and avoid strategies that look profitable on a dashboard but deliver less than expected.

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Why Vault APYs Differ From Realized Returns

APY is an annualized estimate based on yield assumptions. Realized returns measure what your position actually earned over a specific period.

The main reasons they differ are:

Changing yields: Lending rates and trading fees fluctuate with borrowing demand and market activity.
Temporary incentives: Reward tokens can inflate advertised APY without improving the underlying strategy's yield.
Fees and costs: Management fees, performance fees, gas, swaps, and withdrawals reduce net returns.
Asset-price changes: Depegs, volatile tokens, and liquidity losses can outweigh earned yield.
Compounding assumptions: Advertised APY may assume frequent reinvestment that does not happen automatically.

A useful comparison separates native yield, token incentives, and costs. This reveals whether a vault's returns come from its underlying strategy or temporary rewards.

Case Study 1: A Lending Vault With a Falling Borrow Rate

Stablecoin lending vaults earn interest by supplying assets to borrowing markets. Their yields change as borrowing demand and market utilization change.

Suppose you deposit $10,000 into a vault advertising 10% APY. If its average net yield falls to 5% and you withdraw after six months, your earnings would be approximately $250 before personal transaction costs, assuming a constant 5% simple rate during that period.

The initial APY suggested a higher return, but it reflected a rate that did not persist.

When evaluating lending vaults such as those built around Morpho, check:

Historical realized APY over 30 and 90 days.
Underlying lending markets and allocation concentration.
Borrowing demand and dependence on token incentives.
Withdrawal liquidity, collateral quality, and bad-debt exposure.

Image source: Morpho vault

Case Study 2: Token Incentives Inflate the Headline APY

Some vaults combine lending income with token rewards. Their advertised yield can look attractive even when the underlying strategy earns relatively little.

Consider an illustrative vault offering 4% from lending and another 6% from token incentives. If the incentives last only three months and the base yield stays at 4%, the approximate first-year return would be 5.5% before fees and token-price changes, assuming simple accrual and no compounding.

The advertised 10% rate would therefore overstate the return available over the full year.

Before depositing, check:

Whether rewards are paid in the deposited asset or a separate token.
When incentives expire and whether allocations can change.
Whether claiming or selling rewards creates additional costs.
Whether advertised rewards are liquid tokens or points without a realizable market value.

For a more detailed breakdown, see Measuring Real APY vs Incentive APY in Mixed Vault Portfolios.

Case Study 3: Trading Fees Do Not Guarantee a Profit

Liquidity vaults can earn trading fees while losing value because of asset-price changes. A pool on Curve Finance, for example, may generate fees but expose depositors to depegs and changes in pool composition.

Suppose a vault advertises 8% annualized yield, but one of its assets loses its peg. Trading fees may not offset the resulting loss, leaving you with a negative total return despite positive fee income.

Before depositing, evaluate:

Pool composition: Are the assets exposed to the same risks?
Trading volume: Is fee income consistent or driven by a short-lived spike?
Impermanent loss: Could changing asset prices leave you worse off than holding the tokens?
Exit liquidity: Could slippage or withdrawal restrictions reduce your proceeds?

Image source: defillama.com/protocol/curve-finance

How to Compare Vaults Properly

Vault type	Main yield source	Main risk to realized returns
Lending vault	Borrower interest	Falling rates and bad debt
Incentive-driven vault	Base yield plus token rewards	Expiring incentives and falling reward prices
Liquidity vault	Trading fees and incentives	Depegs, impermanent loss, and slippage

Rates can differ across tracking platforms because they use different time windows, fee assumptions, and reward calculations. Read to understand why the same vault can display different yields on different platforms.

Metric	What to check
Current APY	Present rate, not a guaranteed return
30-day and 90-day performance	Whether recent yields are sustainable
Reward APR	How much comes from incentives
Fees	Protocol fees and your transaction costs
Withdrawal conditions	Liquidity limits, queues, and slippage

Rates can also differ across tracking platforms because they use different time windows and reward assumptions.

How to Calculate Your Realized Return

For a deposit and withdrawal in the same asset, use:

For example, if you deposit $10,000, withdraw $10,200, and pay $50 in additional costs, your net profit is $150, or 1.5% over the holding period.

Include rewards you actually received, but subtract costs not already reflected in the withdrawal value. For volatile assets, also measure performance in dollars because a positive token-denominated return can still represent a dollar loss.

My Take

I would prioritize sustainable net yield, realized performance, liquidity, and security over headline APY. A lending vault with transparent allocations and a lower but more dependable yield can be preferable to a strategy relying on temporary incentives.

Before depositing, compare 30-day and 90-day performance, identify the sources of yield, inspect withdrawal conditions, and estimate your own costs. Avoid vaults whose unusually high APY cannot be explained by a clear and verifiable source of income.

Conclusion

Vault APYs differ from realized returns because rates change, incentives expire, fees accumulate, and asset prices move. The most useful comparison is the return you can reasonably expect after costs and risks, not the largest number on a dashboard.

Check historical performance, verify the yield sources, and understand how you can withdraw before committing funds.

FAQs

1. Why is my realized vault return lower than the advertised APY?

The advertised rate may assume that current yields and incentives continue throughout the year. Your actual return reflects changing rates, costs, rewards, and asset-price movements.

2. Is realized APY more reliable than current APY?

Realized APY shows historical performance over a defined period. It does not guarantee future returns.

3. Do token incentives count as real yield?

Rewards contribute to total returns when they have realizable value. Their prices can fall, and claiming or selling them may incur costs.

4. How long should I check a vault's performance before depositing?

Compare 30-day and 90-day performance when reliable data is available. Check whether strategy changes or expiring incentives make those averages misleading.

5. Can a vault with positive APY lose money?

Yes, because depegs, exploits, bad debt, or asset-price losses can exceed the yield earned. Positive APY does not guarantee a positive total return.

References

Morpho Documentation: https://docs.morpho.org/developers/api/morpho-vaults/

Morpho, Yield and Fees: https://docs.morpho.org/developers/earn/concepts/yield-fees/

Curve Finance Documentation: https://docs.curve.finance/

DeFiLlama Yield Server: https://github.com/DefiLlama/yield-server

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About the Author: Chanuka Geekiyanage

Chanuka is a content writer, editor and contributor at Panaprium, specializing in long-form editorial articles. He conducts in-depth research and produces well-structured, carefully edited content with a strong focus on clarity, SEO best practices, and consistent formatting. His work spans lifestyle, fashion, wellness, and technical topics, and all articles are reviewed and refined to meet Panaprium’s editorial standards.

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