How the ETF look-through calculation works
For each fund, the X-Ray multiplies the portfolio allocation by each underlying holding weight. If the same company appears in several funds, those contributions are added.
When complete holdings are unavailable, the tool creates a separate unobserved remainder for each ETF instead of assuming that missing holdings do not exist. Results are explicitly labeled by observed coverage. In directional top-holdings mode the effective-exposure metric is withheld entirely: compressing each fund's large unobserved remainder into a single block would materially overstate concentration, and the unobserved holdings may themselves overlap across funds. Effective exposures are reported only in verified full-holdings mode, after the dataset passes coverage checks.
Why this differs from pairwise ETF overlap
A pairwise comparison asks how similar two funds are. A portfolio X-Ray asks how much of the investor's total allocation reaches each underlying company after accounting for fund weights. Continue with the concentration calculator or learn how Guardfolio performs portfolio risk monitoring after synchronized updates.
Worked example with directional data
With the fund dataset currently published on this site (named top-10 holdings per fund, updated 2026-05-19), a portfolio weighted 50% VOO, 30% QQQ, and 20% SCHD produces this directional result: named top holdings account for about 42% of total portfolio weight, the largest observed company exposure is NVIDIA at roughly 6.7% (reached through both VOO and QQQ), and 8 named companies appear in more than one fund. The remaining 58% of portfolio weight is unobserved, so this is a partial view, not complete look-through concentration. This example will be regenerated with verified figures and provider dates once the full-holdings dataset is published.
Questions
Does the X-Ray use my brokerage account?
No. This public X-Ray uses only the ETF symbols and weights entered in the browser.
What does observed weight mean?
Observed weight is the share of the entered ETF portfolio represented by named holdings in the available dataset. A partial dataset leaves the remaining fund exposure unassigned rather than presenting it as zero.
Why can one company appear through several ETFs?
Popular broad-market and growth ETFs often own the same large companies. The X-Ray adds each fund's contribution to show repeated effective exposure.
Why are effective exposures missing in directional mode?
Top-holdings data leaves most of each fund's weight unobserved, and the unknown holdings may also overlap across funds, so no reliable effective-exposure number can be computed. The metric is reported only in verified full-holdings mode, after the dataset passes coverage checks.