Prop 1031: Alloyed BTC: Increase nBTC static limit to 60%

This proposal increases the static rate limit of nBTC within Alloyed BTC from 35% to 60%.

Alloyed BTC

Alloyed BTC (allBTC) unifies Bitcoin liquidity across bridges behind a single onchain asset. Each constituent carries a static rate limit capping its maximum share of the alloy, so that Osmosis's exposure to any one bridge is bounded even if that bridge is compromised. The alloy currently holds:

• WBTC, natively issued on Osmosis (75% cap)
• WBTC.eth.axl, via Axelar from Ethereum (75% cap)
• cbBTC.axl, Coinbase Wrapped BTC via Axelar (75% cap)
• WBTC.eth.atom, via the Cosmos Hub's Eureka (75% cap)
• nBTC, via the Nomic bridge (35% cap)

nBTC is the only constituent still held below 75% and the only connection directly to Bitcoin; it now sits at roughly 33% of the alloy, effectively at its cap. With nBTC pinned at the limit, further Bitcoin deposits through Nomic are rejected, adding friction for users bridging via that route.

Live capacities and compositions can be viewed on the Alloyed Asset Dashboard.

Rationale

nBTC's static limit has been raised steadily as the Nomic bridge has demonstrated reliability and demand has grown, from an initial 5% to the current 35%:

• Proposal 815: initial static limits, nBTC at 5%
• Proposal 867: nBTC increased to 10%
• Proposal 893: nBTC increased to 20%
• Proposal 899: nBTC increased to 35%

Raising nBTC to 60% gives it meaningful headroom for continued growth while keeping the Nomic bridge to a more conservative bound than the 75% applied to the WBTC and Axelar-bridged constituents. As with prior adjustments, the limit can be reduced by a later governance action if observed demand settles or risk conditions change.

Proposed change

This proposal updates a single rate-limiter parameter. It involves no contract migration or code change and is fully reversible by a subsequent governance action.

Forum Post: https://forum.osmosis.zone/t/alloyed-btc-increase-nbtc-static-limit-to-60/4073