Portfolio Tools
Portfolio X-Ray: See the Exposures Hidden Inside Your Holdings
Look through your positions to the exposures underneath them.
Enter your holdings and see top-level allocation, concentration, a portfolio-weighted look-through of underlying exposure, and a weighted fee estimate, each labeled with how much of the portfolio it actually covers.
Direct Answer
A portfolio X-ray looks through your holdings’ labels to estimate the exposures underneath them, because owning several positions does not guarantee diversification: a broad-market fund, a growth fund and a technology fund can place much of their weight in the same handful of companies. This tool reports allocation, concentration, weighted fees and combined look-through exposure from holdings you enter, each with a coverage figure showing how much of the portfolio it could actually classify. It does not fetch or verify a fund’s current holdings, so every result is a snapshot of what you typed rather than of the market today.
What Does a Portfolio X-Ray Show?
A portfolio X-ray looks through your holdings' labels to estimate the exposures underneath them. Owning several positions does not guarantee diversification; those positions can share the same underlying companies, sectors, or factors. Enter your holdings below to see allocation, concentration, weighted fees, and a combined look-through exposure, each with a coverage figure showing how much of the portfolio the tool could actually classify.
Why Fund Count Is Not the Same as Diversification
A portfolio built from a broad-market index fund, a growth fund, and a technology fund holds three separate positions on a statement. Underneath, all three can place a large share of their weight in the same handful of mega-cap companies. Counting positions tells you how many products you hold; it does not tell you how concentrated the actual economic exposure underneath them is.
The same blind spot applies to fixed income: a bond fund's headline label does not show whether its duration or credit exposure is concentrated in a narrow slice of the market. Look-through analysis moves the question from "how many things do I own" to "what do I actually own, once the wrappers are opened."
Portfolio X-Ray Calculator
Every figure comes from what you type in below. Nothing is fetched from a brokerage or market-data provider, and nothing is sent to Swoopr Investment's servers. Educational tool only, not investment advice.
Concentration Is More Than the Largest Position
A portfolio with ten equal 10% positions is less concentrated than one with a single 70% position and nine small ones, even though both have ten holdings. This tool uses the Herfindahl-Hirschman Index (the sum of each position's squared weight) and reports its inverse as an effective number of holdings: a plain-language summary of how many equally weighted positions the portfolio's concentration is equivalent to.
Hypothetical example, for education only.
A portfolio of 5 equal 20% positions has an HHI of 0.20 and an effective number of holdings of 5, exactly matching its raw count. A portfolio where one position is 60% and the other four share the remaining 40% equally (10% each) has an HHI of 0.6² + 4×0.1² = 0.40, giving an effective number of holdings of 2.5, less than half its raw count of 5, because the dominant position drives the outcome.
Look-Through Overlap Is Not Automatically a Problem
If you disclose a fund's underlying constituent holdings, the tool aggregates every occurrence of the same name across your whole portfolio, whether you hold it directly or through a fund. Finding that a company shows up multiple times is not automatically a mistake. An investor may deliberately add a sector fund on top of a broad index to intentionally overweight that sector. The useful question this tool helps answer is whether the resulting combined exposure matches what you intended, not whether overlap is exactly zero.
For a direct, two-fund overlap comparison using each fund's own top holdings, see the ETF Overlap Analyzer. Portfolio X-Ray is complementary: it works across your entire portfolio (any number of positions, any asset type) and aggregates a shared name across both direct and fund-held exposure, which a two-fund comparison alone cannot show.
Why Coverage Percentages Matter Here
Fund holdings disclosures vary in frequency, completeness, and format, and this tool has no external holdings feed to fall back on: every classification, expense ratio, and underlying-holdings breakdown comes from what you type in. If you list a fund position without naming its constituents, that portion of the portfolio cannot be looked through, and the calculator reports it as uncovered rather than guessing. The results panel always states what share of the portfolio each figure actually covers, so a partial breakdown is never presented as if it were complete.
| Output | What it measures |
|---|---|
| Asset allocation | Portfolio weight grouped by the asset type you entered; unlabeled positions bucket into "Unclassified." |
| Effective number of holdings | Concentration summary, 1 ÷ HHI, using position-level weights. |
| Weighted fee estimate | Portfolio-weighted expense ratio, counting only fund positions where you entered an expense ratio. |
| Look-through holdings | Combined weight per underlying name, aggregated across every position that discloses it, direct or fund-held. |
| Coverage percentages | Share of total portfolio weight each figure above was actually able to classify, fee, or look through. |
Limitations and What This Tool Does Not Do
- No live holdings data. Fund constituents, expense ratios, and asset types all come from what you enter; the tool does not fetch or verify them against a fund's actual, current holdings disclosure.
- No sector, region, or duration breakdown. Those require either a licensed classification feed or per-position tagging this MVP does not yet collect; the current build focuses on allocation, concentration, look-through overlap, and fees.
- Static snapshot. Fund holdings change over time. A breakdown you build today can be stale by the time a fund's next disclosure is published.
- Not a full risk model. The Herfindahl-Hirschman Index summarizes concentration by weight; it does not capture correlation, volatility, or how positions behave together.
- Educational only. This tool does not tell you what to buy, sell, hold, or how to allocate. It does not account for your objectives, taxes, time horizon, or risk tolerance.
Privacy and Data Handling
All calculations run in your browser. Holdings you type into this calculator are not sent to Swoopr Investment's servers, stored, or logged; closing or reloading the page clears them. No account or sign-in is required to use this tool.
Portfolio X-Ray FAQs
Does owning more funds always improve diversification?
No. Different funds can hold many of the same underlying companies, sectors, or regions. A broad-market fund, a growth fund, and a technology fund are three separate positions, but their look-through exposure to a handful of large companies can still overlap heavily. Fund count is not the same as exposure diversity.
What does effective number of holdings mean?
It is a concentration summary, the inverse of the Herfindahl-Hirschman Index (1 divided by the sum of each position's squared weight). A portfolio of 20 positions where one holding is 60% of the total behaves, in concentration terms, much closer to a 2-holding portfolio than a 20-holding one, and the effective number of holdings reflects that.
Is overlap between two funds automatically a problem?
No. Overlap can be a deliberate choice, for example adding a sector fund on top of a broad index to intentionally overweight that sector. The useful question is whether the resulting combined exposure matches what you intended, not whether overlap is exactly zero.
Why does the tool show a coverage percentage instead of a complete breakdown?
Because look-through analysis is only as complete as the underlying holdings you disclose. If you list a fund position without its constituent holdings, that portion of the portfolio cannot be classified further, and the tool reports it as uncovered rather than guessing. Treating an incomplete breakdown as if it were complete would overstate what is actually known.
Does Portfolio X-Ray connect to my brokerage account?
No. Every figure comes from positions you type in yourself. Nothing is fetched from a brokerage, and nothing you enter is sent to Swoopr Investment's servers or saved between visits.
References
- SEC Investor.gov: Mutual Funds: background on fund structures and where to find a fund's holdings disclosures.
This calculator analyzes user-entered, hypothetical portfolio data. It is not investment advice, and results are only as complete as the coverage percentages shown alongside them.