ADR-0026: a coin chain's anchoring is subsidised in SOL until the rent comes back

Solieum's own chains charge their fee in their own coin and anchor to Solana, which is paid for in SOL.

Status: accepted. Dated 2026-09-29.

Status: accepted, 2026-09-29. Decided by the owner after the cost of anchoring chain 9232 was measured. Builds on ADR-0017 (the rent reclaim that is built and deployed nowhere) and ADR-0025 (the coin and the token are one asset). The measurement and the arithmetic are in docs/notes/coin-chain-settlement-economics-2026-09-29.md.

1. Context

Solieum's own chains charge their fee in their own coin and anchor to Solana, which is paid for in SOL. Measured on 9232 on 2026-09-29: an anchored block costs 3,620,360 lamports, of which 3,520,360 is rent that is not reclaimed today — 97%. Signature fees are 5,000. Rent does not grow with the payload, so a block with a thousand transactions costs what a block with one costs.

Against that, the chain earns the sequencer's half of its 5,000-base-unit fee: 0.0000025 SULI per transaction. Covering one block requires

which no believable combination of price and volume satisfies. The asset also has no market to be sold into, so the revenue cannot buy the SOL the chain spends even in principle.

2. Decision

1. A coin chain's anchoring is an operator subsidy, paid in SOL, and is described that way. No document, page or talk says or implies that a coin chain funds its own settlement, or that its fee burn offsets its costs.

2. No self-funding claim is made until rent reclaim is deployed and re-measured on a cluster. ADR-0017 §6.3–6.4 exists and is deployed nowhere; rentReclaimable reads false. With it, the break-even becomes transactions × price ≈ 2 — roughly 700× better, and arguable. Without it, it is not.

3. Anchoring cadence is the cost lever, not the fee. Because cost is per block and nearly independent of payload, cost per transaction falls with block fullness. A chain that anchors every block at low volume is choosing to pay ~0.0036 SOL per transaction for verifiability. That is a legitimate choice on devnet and a decision to take deliberately anywhere else.

4. The float is sized and alarmed in blocks of runway, not in SOL. The node reports payer_status.blocksOfRunway; a balance alone means nothing because the cost per block moves with rent and cadence.

5. One payer per chain, its own key, funded from the faucet on devnet. Never from another chain's payer (runbook §1.1: one key, one job).

3. Consequences

• The white paper's economics section and the site's fee pages say what the subsidy is, rather than presenting the burn as an offsetting force. The burn destroys 0.0000025 SULI per transaction — 400,000 transactions per coin — so it is a fee-policy mechanism, not a supply story, and the documents say so.
• Deploying rent reclaim moves from "someday" to the precondition for any economic claim about coin chains. It is the highest-leverage unbuilt-but- written thing in the project.
• A coin chain that anchors continuously is a budget line: ~156 SOL/day at a block every two seconds. Anything beyond devnet needs that number agreed before it runs, not after.
• Nothing on-chain changes. This is a decision about what is claimed and what is measured before claiming it.

4. What this does not decide

The issued asset's supply, price or market — ADR-0018 §5 and ADR-0025 leave those open, and none of them changes the arithmetic above. Nor does it decide whether a future coin chain should anchor at all: anchoring buys outside verifiability, and that is worth a subsidy on a chain whose value is test value. It decides only that the subsidy is stated.