Methodology
Lumina ETF decomposes ETF allocations into weighted underlying stock exposure using the latest validated local snapshot available for each supported ETF.
Overlap by weight
For every stock shared by two ETFs, take the smaller holding weight. The sum of those minimum weights is the pair overlap.
Portfolio true exposure
For each holding, multiply the ETF allocation by that ETF's holding weight. Add contributions from every ETF containing the stock.
Percent and amount modes
Both modes normalize the entered values to 100% before calculation. Amount mode does not use live prices, brokerage data, tax lots, or cost basis.
Sector and country exposure
Stock exposures are grouped through a canonical security master so issuer-specific labels do not fragment the result. Missing classifications remain visible as Unknown rather than being guessed.
Coverage
Coverage is the allocation-weighted holdings coverage reported for each ETF. Production launch remains blocked until source rights, caching rights, and classification coverage are confirmed.
Benchmark comparison
For a selected stock or sector, Lumina ETF compares portfolio exposure with a benchmark ETF proxy snapshot: SPY for S&P 500, VTI for Total US Market, QQQ for Nasdaq 100, and VT for Global Equity. These proxy ETFs use the same issuer snapshot pipeline as supported portfolio ETFs. The system can check them daily, but issuer as-of dates may update daily, monthly, or on another schedule. This is not real-time official index constituent data.
Hypothetical scenario impact
Selected-stock detail can estimate a mechanical portfolio impact: stock exposure multiplied by an assumed stock move. The default -10% scenario is hypothetical, assumes the rest of the portfolio is unchanged, and is not a forecast.
What-if simulation
Simulated ETF weights are normalized with the same allocation rules as the main analyzer. They remain separate from the original portfolio until the user explicitly applies them.
Why results can differ
Data dates, holdings coverage, classification systems, and treatment of cash or derivatives can differ across data sources.
For educational purposes only. Not investment advice.