Proof of Reserves for tGBP: pricing by backing, not by trading

DIA deployed a Proof of Reserves oracle for tokenised GBP (tGBP) on Ethereum, with planned expansion to the other five chains where the token is deployed. The feed is part of DIA Value, the fundamental valuation product within the DIA oracle stack.

tGBP is issued by BCP Technologies, an FCA-registered cryptoasset firm operating in the United Kingdom since 2021. The token launched in June 2025 after participating in the FCA Regulatory Sandbox, and crossed $30M in market capitalisation in April 2026, ranking it among the top 5 non-USD stablecoins globally per RWA.xyz. Reserves are held in cash, GBP money market funds, and short-term UK gilts with regulated banking partners. Monthly attestations are published on the tGBP transparency page.

As of April 2026, the asset has roughly £20M in market capitalisation against around £3M in monthly volume on Coinbase and Kraken. The structural mismatch between those two numbers is the reason this feed exists.

The tGBP feed runs on DIA’s decentralised oracle network, with oracle updates finalised on Lasernet, its rollup-based Ethereum L2. Every update is recorded on a public chain, so a consumer of the feed can independently reconstruct what was published, against which inputs, and when.

The data layer is a network of Feeders, independent nodes that aggregate, format, and distribute structured data onto Lasernet. Each feed is processed by more than ten such nodes, with their consensus determining the values that reach the on-chain pipeline.

For tGBP, the Feeders read reserve balance data from BCP’s regulated custodians: Banking Circle, Clear Junction, and Swissquote for cash, and Interactive Brokers for short-term UK gilts. Balances are normalised into a common GBP unit and summed to derive total GBP reserves. In parallel, the Feeders query totalSupply() on the tGBP contract on each of the six chains where the token is deployed, summing to a global circulating supply. The published price applies a conservative floor:

GBP_Price_Per_tGBP = min(1.0, Total_GBP_Reserves / tGBP_Total_Supply)

The result is converted to USD using a GBP/USD reference price feed. This feed is constructed with independent Feeders pulling live rates from multiple 24/7 FX sources, consensus filtering selects the most recent value within a 2/3 agreement window, and a 24/5 FX guardian blocks updates that deviate beyond a configured threshold to protect against weekend dislocations and source manipulation. The combined feed publishes on a push schedule.

A regulator, an issuer’s risk team, or a vault curator can trace the computation backward to the published reserve attestations and forward to the on-chain price, without taking DIA’s word for any link in the chain. Proof of Reserves does not eliminate the off-chain trust boundary at the auditor and the custodian; what the on-chain pipeline contributes is making that boundary continuously checkable and the computation reproducible by anyone reading the contract.

For an issuer evaluating this kind of integration, the shape is recognisable: reserve balance data feeds the Feeder network, the network handles aggregation, consensus, on-chain publication, and verification. There is no bespoke off-chain processing layer between the data and the published price, and there are no protocol changes required on the issuer’s token contract.

When tGBP is fully backed, the feed reads 1.00. When it is over-collateralised, the feed still reads 1.00, because for a redeemable stablecoin, par is the maximum honest valuation. When reserves ever fall short of supply, the feed discounts immediately and proportionally in the next published update, without waiting for a thin secondary market to discover the shortfall.

The practical effect is that the feed tracks the issuer’s actual obligation. A vault or lending market consuming this feed underwrites reserve adequacy, which is the real default risk for a redeemable stablecoin, rather than the noise of a £5K daily print on a single venue.

A reserve-backed price is the missing precondition for a regulated stablecoin to function as institutional collateral. Spot prints from a thin venue are not a basis on which a vault can size positions; an oracle that tracks the issuer’s actual obligation is. With this feed live, tGBP moves from being a GBP stablecoin that sits upstream of DeFi to being an asset with a defensible on-chain valuation that AAA vault platforms and risk curators can evaluate on the same terms they apply to any other reserve-backed collateral.

The same method applies to any fiat-pegged, fully-backed stablecoin whose issuer can make reserve positions visible to an oracle on a reliable cadence. The constraint is not the denomination or the jurisdiction; it is whether the reserves can be read or attested often enough to support a live feed. For regulated issuers whose reserves already sit in auditable banking infrastructure, that precondition is usually already there. The work is connecting it to a feed that prices the asset on its actual terms and runs on an architecture their compliance team can point to.