The validator yield stack components
ETH staking validators earn yield from three sources: issuance (new ETH created by the protocol), tips (transaction priority fees paid by users), and MEV (Maximal Extractable Value, fees captured by reordering transactions). These three streams sum to the total validator reward. Issuance is predictable and decreases over time as a percentage of stake. Tips and MEV are variable and can be a large portion of yield in high-activity periods.
Operators (Lido, Rocketpool) who run validators take a commission (5-15%) from these rewards. A staker might earn 3.5% gross yield, minus the operator's cut, netting them 2.9-3.3%. Different staking protocols have different fee structures; solo stakers earn the full gross yield but require technical setup and ongoing maintenance.
Why MEV is volatile
MEV grows during periods of high network activity and congestion, when users are competing for block space. Sophisticated MEV extractors use flash loans and sandwich attacks (inserting their own transactions before and after a user's transaction) to capture the difference. During low-activity periods, MEV is nearly zero. This volatility means staking yield can double or halve with market conditions. Some stakers argue that MEV extraction is rent-seeking and reduces network efficiency, prompting ongoing research into MEV-resistant designs like PBS (Proposer-Builder Separation).