Cardano stake pools pay less once they cross the saturation point

For anyone staking $ADA on the Cardano network, the pool you choose matters more than many delegators realize. A key reason is the saturation mechanic built into Cardano's proof-of-stake protocol.

How Saturation Works

Every Cardano stake pool has a ceiling on the amount of delegated stake it can hold before returns start to decline. According to Cardano's official documentation, saturation is designed to prevent centralization by encouraging delegators to spread their stake across multiple pools, and by incentivizing operators to launch new ones. Once a pool crosses that threshold, rewards per delegator fall, which naturally steers stake toward smaller, less congested pools.

The saturation limit is not a fixed number. It is calculated dynamically based on the total staking supply divided by a protocol parameter called "k," which represents the target number of pools on the network. The current k value is 500, which puts the saturation ceiling at roughly 76 million $ADA per pool.

Alongside saturation, the concept of "pledge" also influences rewards. Pledge is the amount of $ADA a pool operator personally stakes in their own pool. Per @Cardano's documentation, a higher pledge improves a pool's rewards score through the protocol's a0 parameter, effectively rewarding operators who have more skin in the game.

A Proposal to Double the Pool Target

A governance action has been drafted to increase k from 500 to 1,000. The Cardano Incentives Working Group's proposal argues that raising k would improve decentralization and broaden the economic base for more stake pool operators by encouraging $ADA holders to delegate to a wider range of pools. If enacted, the change would roughly halve the saturation cap to around 38 million $ADA per pool.

The proposal has not yet been enacted. Community opinion is divided. A 2023 poll facilitated by the Cardano Foundation found that, measured by pool count, 69% of participating pools backed raising k to 1,000, while larger pools by stake tended to prefer keeping it at 500. Since the Plomin Hard Fork in January 2025, all updatable parameters are governed by $ADA holders, meaning a sufficiently supported governance action could change k without requiring approval from the original development team.

For delegators, the practical takeaway is straightforward: check a pool's saturation level before committing stake, and be ready to redelegate if a pool starts to fill up. Monitoring these metrics is one of the simplest ways to protect staking returns on the Cardano network.

Sources:
Cardano.org: Stake Pool Delegation
Cardano Incentives Working Group: K=1,000 Governance Action Draft
Lido Nation: Optimal Pool Count Analysis