Class Birth-Year Realized Cap
Realized cap decomposed across all birth-year cohorts (from genesis 2009 to current year, auto-extending) - the cost-basis view of the entire circulating supply. Each layer aggregates the USD value at which the cohort's UTXOs were last moved.
What is it?
This metric decomposes Bitcoin's total realized cap by the calendar year in which each UTXO was mined. A cohort's realized cap is the sum of USD acquisition costs for that year's still-unspent UTXOs. Eighteen cohorts emerge (Class 2009 to 2026). The sum of all eighteen layers equals total realized cap at any date. This view reveals the economic concentration of Bitcoin supply by investor generation.
How to read
The Y axis shows realized cap in USD stacked (log scale recommended to visualise old cohorts very small in USD vs recent massive ones). Bottom layer = Class 2009 (very small in USD because cost basis ~$0). Dominant layers = years with high acquisition cost (2017, 2021, 2024). Relative layer order structurally differs from the supply decomposition: a cohort with few coins but high cost basis can weigh more in realized cap than a cohort with many coins at low prices.
Key zones
Bull-market cohorts (2017, 2021) typically dominate the realized cap decomposition because their average cost basis is high. A rapid expansion of the active year's cohort indicates strong capitalisation marked by new entrants at high prices. Comparing the ratio 'realized cap class year / supply class year' gives the average cost basis of each cohort - revealing that generation's buy sentiment.
What to observe
Track the active year's cohort growth: its rapid acceleration marks fresh capital inflow phases. The decrease of an older cohort (e.g., 2017) at a cycle peak reflects partial spends where holders take profit (that year's realized cap decreases because coins leave the cohort). Comparing realized cap dominance between Class 2017 and Class 2021 measures economic concentration of the two most recent bull cycles.
Historical context
The original realized cap (Coinmetrics, 2018) treats the entire supply as a single aggregate. Decomposition by birth year extends this analysis by isolating cumulative acquisition cost per generation, revealing the economic stratification of the investor base. Historic bull markets (2013, 2017, 2021) emerge visually as dominant layers, witnesses of capital injected during those periods.
Expert notes
The class_{year}_realized_cap cohorts (auto-extending each January 1st) are deterministic full-node-indexed aggregates from the Bitcoin blockchain (sum of USD acquisition costs of UTXOs filtered by year). The B11 SOP §1.2 exception applies. Trinity audit tolerance 1.5%. The sum of all layers must converge toward total realized cap - a drift > 1% indicates a regression to investigate via TAE chain step 6 RECOMPUTE_C.
Common mistakes to avoid
A cohort's realized cap is not its current market value - it is only the sum of cumulative acquisition costs. A cohort can have a huge realized cap while being at unrealized loss (if current price < average cost basis). Do not naively sum realized cap + supply: they are two different-nature metrics (USD vs BTC). An old cohort (Class 2009) with a near-zero realized cap does not mean it is worthless - its current market value can be huge.
Programmatic access
REST API
curl -sS \
'https://api.trinityinsights.io/api/v1/onchain/class-birthyear-realized-cap/history?days=90' \
-H 'X-API-Key: $TRINITY_API_KEY'MCP server
{
"tool": "get_chart_value",
"metric_id": "class-birthyear-realized-cap",
"timeframe": "1y"
}Required tier: performance. See the pricing grid for the tier list and the MCP documentation for multi-client configuration.
Related metrics
Institutional disclaimer
Trinity Insights is an educational and analytical tool. The metric above does not constitute investment advice. Trinity Insights is not a Crypto-Asset Service Provider (CASP) registered under MiCA Regulation (EU) 2023/1114. See the full disclaimer.