What Horizon changed for delegators

Graph Horizon went live on 2025-12-11. For delegators it changed three things that matter and one that matters a great deal more than the other two.

Provisions: stake now points at a service, not just an indexer.

The structural change under Horizon is that the protocol supports several data services rather than one, and stake is provisioned against a specific service rather than pooled generally.

The Subgraph Service is the first, and today the dominant one. When you delegate, you are backing an indexer’s participation in a particular service, and an indexer’s obligations, and its slashing exposure, are defined by that service rather than by the protocol as a whole.

Practically, today, this is mostly a change in vocabulary for delegators. Its importance is in what it makes possible: as further services arrive, the choice of which service an indexer serves becomes part of what you are selecting when you select an operator, and the risk profiles of different services need not match.

The delegation tax is gone.

Deposits are no longer taxed. The parameter is 0% and it was removed from the protocol, not set to zero pending a change of mind.

This makes entering cheaper and, more subtly, makes moving between indexers cheaper in fees while leaving it exactly as expensive in time. The binding constraint on rotation was always the 28 days thaw, and Horizon did not touch it.

Slashing of delegated stake: the honest version.

This is the one to read carefully, because it is easy to state in a way that is either falsely reassuring or falsely alarming.

Today: delegated stake is Not currently slashable for the Subgraph Service. If your indexer is slashed for misbehaviour, the loss falls on their own stake.

In the code: Horizon introduced the technical capability for delegated stake to be slashed. The documentation says so directly: the capability “is not currently enabled for SubgraphService, but delegators should be aware it may be activated in future protocol upgrades.”

What that means for you: it is a future risk that already exists in the mechanism, and enabling it is a governance decision rather than a rewrite. New data services arriving under Horizon may make different choices, since slashing rules belong to the service.

Alongside this, slashing itself became flexible. Arbitrators determine an appropriate amount based on severity, capped at 10% of the indexer’s stake, with a recommended value of 2.5%. Previously the amount was fixed by the protocol rather than judged.

What did not change.

Worth stating plainly, because a large release invites the assumption that everything moved:

• The 28 days thawing period is unchanged.
• The delegation capacity multiplier is unchanged.
• The direction of the reward cut is unchanged. It is still what the indexer keeps.
• Your return still depends on your indexer allocating stake attentively, and that is still invisible in a headline rate.

What to actually do about it.

• Check which data services your indexer participates in, and expect that list to grow.
• Stop budgeting for a deposit tax. If a tool is still deducting one, that tool is stale.
• Treat delegated-stake slashing as a governance question worth following, not as a present risk and not as an impossibility.
• Read anything written before December 2025 with the assumption that its Horizon content is absent rather than wrong, and its slashing content is out of date.