Methodologies
The Coin Metrics Bletchley Indexes (CMBI) are a comprehensive suite of single-asset, multi-asset and unique crypto asset benchmarks used by leading crypto and traditional financial institutions. This section holds the documents that govern them.
They divide the same way the governing documents for any administered benchmark do, between the numbers and the process. The series methodologies and the cross-cutting frameworks determine how a level is produced: which assets are in an index, how their supply is adjusted, and how the calculation responds to a fork. The policies and governance documents determine how the benchmark is administered: who oversees it, when a published value may be restated, and how complaints are handled. Each document is versioned and published in full, so an index level can be reproduced from them rather than taken on trust.
Series Methodologies
One document per index series, setting out the construction rules for that series in full.
CMBI Single Asset Series
CMBI Multi Asset Series
CMBI Mining Series
CMBI Momentum Series
CMBI Total Market Series
CMBI Ethereum Staking Index
The CMBI Ethereum Staking Index (CMBIETHS) reflects the performance an investor would expect from purchasing and staking Ether. The total return consists of the hourly price return of Ether and the rewards earned from the Ethereum blockchain.
Cross-Cutting Frameworks
These apply across series rather than to one of them, so they are referenced by several of the documents above.
Adjusted Free Float Supply Methodology
Free Float Supply can overcome the imbalance between supply and demand by reducing the weight of a constituent to account for supply that is either restricted, not freely available for purchase or increasingly unlikely to be available to the market. Free float adjustment excludes native units of a cryptoasset that are closely held by controlling groups, government agencies, directors, founders and founder family holdings, investors with vesting schedules and long-term strategic investors (defined herein as holders of tokens that have not moved on-chain in over 5 years).
To the maximum extent possible, Coin Metrics has created a free float adjustment methodology that can be applied consistently, uniformly and objectively across all of our indexes.
This is the adjustment behind the weights published by Index Constituents.
Fork Legitimacy Framework
Cryptoasset networks operate programmatically, where transaction validity is determined by the underlying code upon which the blockchain runs. This code is governed by a set of "consensus rules". There are two types of forks that cryptoassets can undergo:
If a change in consensus rules does not require nodes to implement software changes in order to be compatible with the new set of rules (i.e. backwards compatibility), this is known as a soft fork.
If a change in consensus rules requires nodes to implement new software in order to remain compatible with the new set of rules, this is known as a hard fork.
This framework only considers forks of cryptoassets with Proof-of-Work consensus mechanisms.
Constituent Market Selection
The rules that decide which exchange markets are eligible to feed a CMBI benchmark, including the eligibility criteria and the public nomination process.
Policies and Governance
The administration side. These are the documents to reach for when the question is about how the benchmark is run rather than how a level is derived, which is typically the case for due diligence, audit, and regulatory review.
Related
Index Overview: the index families these documents govern, and the data types published for them.
Fact Sheets: the short-form summary of each series, where these documents are the long form.
Index Levels: how the calculations described here behave in practice.
Talos Exchange Scorecard: the exchange evaluation that feeds candidate market selection, documented under Market Data because it is used outside the indexes too.
Indexes Glossary: definitions of the index terms used across these documents.
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