Know What YouActually Own.

Opened up, far fewer companies than the number of funds suggests; and usually the same mega-caps inside several of them at once. A scan replaces each fund with its constituent holdings, multiplies every company’s weight inside the fund by that fund’s share of your money, and sums the same company across every position you own. Worked example, with illustrative weights rather than current fund data: 40% of a portfolio in a total-market fund holding 6% Apple is 2.4% Apple; another 25% in a tech fund holding 14% Apple adds 3.5%; hold 3% Apple directly and the real weight is 8.9%. Three lines on a statement, one company. When we have the fund’s SEC N-PORT filing, a scan uses every constituent that real source publishes rather than a fixed slice of the largest positions. That is still not a portfolio in full: a fund we have no holdings list for, most often an international ETF, contributes nothing, and crypto looks through to nothing. So each scan reports a coverage ratio for how much of yours it could see through, and the arithmetic and its limits are on the methodology page. The scan is free and needs no account.Link to this answer

ETF overlap is when two or more funds in your portfolio hold the same underlying stocks, so you own those companies several times over without seeing it. It matters because overlapping funds quietly concentrate your portfolio: the S&P 500 makes up most of a total US market fund by weight, so holding an S&P 500 ETF alongside a total-market ETF adds very little diversification — the same mega-cap stocks dominate both. A brokerage statement can’t show this, because it lists each fund as a single line. To find your real exposure you have to look through each ETF to its constituent holdings, multiply each stock’s weight inside the fund by the fund’s weight in your portfolio, and sum across every position — which is exactly what a PortLens scan automates. Or start with the numbers for popular fund pairs.Link to this answer

Look-through exposure is your portfolio measured at the level of underlying companies rather than tickers. Each fund is replaced by its constituent holdings at their effective weights — a 20% position in an ETF that holds 7% Apple contributes 1.4% Apple to you — and exposures to the same company are summed across every fund and direct holding. The result answers questions a holdings list can’t: how much of your portfolio is really in one stock, one sector, or one country once every wrapper is opened. Institutions have run this analysis for decades; PortLens computes it in about a minute, along with effective holdings — a concentration measure showing how many equally-weighted positions your portfolio actually behaves like.Link to this answer

Measure it underneath your funds, not from the fund weights on your statement. A statement shows how your money is packaged — 40% in one fund, 25% in another — while your allocation is what those funds hold beneath the wrapper, added together across all of them. A free PortLens scan reports that combined view: your weight in each of your ten largest underlying companies, how many of your funds each one reaches you through, your largest sector within the portion that has sector data, effective holdings, and the coverage ratio for company look-through. Bonds and cash inside your funds show up too, named by type (US Treasury, government agencies, corporate bonds and so on) with the share of your money in them, though there is no bond analysis such as yield or duration. A fund whose holdings can’t be resolved, most often an international fund, shows up in that coverage ratio instead of in your top names.Link to this answer

Count your independent sources of risk, not your tickers. A useful check has three steps: look through your funds to underlying companies (overlapping ETFs can make ten funds behave like one), measure concentration with effective holdings (1 ÷ the sum of squared weights — a portfolio of one 50% and two 25% positions behaves like 2.7 equal positions, not 3), and check the spread of that looked-through portfolio across sectors and geographies. A free PortLens scan runs all three and returns a 0–10 diversification score built from holdings count, sector and industry spread, look-through concentration, and geography — with the formula public on the methodology page.Link to this answer

There’s no universal threshold — what matters is whether overlap concentrates you beyond what you intended. Two S&P 500 trackers from different providers overlap almost completely, so the second fund adds the same companies again; a growth fund stacked on a tech fund and a Nasdaq-100 fund can put the same few mega-caps at a third of your portfolio. The practical test is your top-10 looked-through weight and your effective holdings count: if opening your funds shows far fewer separate positions than your statement suggests, overlap is why. PortLens shows both numbers for your actual portfolio, so the “too much?” question gets a measured answer instead of a rule of thumb.Link to this answer

Yes — PortLens runs two, both free. The ETF overlap checker — which needs no account — takes two tickers and returns the share of weight the funds hold in common, computed as the sum of the smaller of the two weights over every stock both funds hold. A full portfolio scan does the same job across all the funds we have holdings lists for, up to 20 holdings with no account, more with a free account, rather than a pair at a time. What to know before relying on either: a computed pair needs at least 25 constituents for each fund, taken from the fund’s SEC N-PORT filing, and a pair below that gets a stated refusal naming the fund that fell short; two tickers the SEC identifies as share classes of one registered fund get a declared 100% without constituent arithmetic. The filing’s holdings can be weeks or months old, so a computed result is anchored to the older of the two dates and prints both. None of it is real-time.Link to this answer

The checker is a two-ticker calculator, and pairwise comparison stops being the right question once you hold three or more funds — what you want then is the combined result across all of them. A free PortLens scan takes the whole list — up to 20 holdings with no account, more with a free account — and reports your weight in each of your ten largest underlying companies, how many of your funds each one reaches you through, effective holdings as a concentration measure, and a coverage ratio for how much of the portfolio it could look through. Read that coverage ratio: a fund we have no holdings list for — most often an international ETF — contributes nothing to the look-through, and crypto looks through to nothing at all.Link to this answer

Yes — the PortLens scan runs with no account and no payment, and here is exactly what that covers, so you can check it against anything else. You type holdings in by hand: there is no broker or bank connection and no CSV import, so nothing is linked to your accounts. Signed out you can analyze up to 20 holdings, and a free account lifts that cap. The free result reports its look-through coverage ratio alongside exposure to the underlying companies, overlap between the funds we have holdings lists for, effective holdings and top-10 concentration, your largest sector within the portion that has sector data, portfolio beta against the S&P 500 total return, a 0–10 diversification score, and your weighted expense ratio with the coverage it was computed over and any fund with no published ratio named rather than counted as zero. Return projections start free with two models, CAPM and your own trailing history. Pro adds the Insights set, the per-fund cost split, and three more projection models — Monte Carlo, a macro model, and a Fama-French factor regression. Every formula is on the methodology page.Link to this answer

No, and the difference is worth knowing before you try it. A tracker connects to your brokerage, follows your balance day to day and reports gains and losses. PortLens does none of that: there is no broker or bank connection and no CSV import, holdings are typed in by hand, and market data is cached rather than streamed live. It is an analyzer. The job is telling you what your portfolio is made of once the funds we have holdings lists for are opened into their constituent holdings: which companies you own through several funds at once, how concentrated that really leaves you, and how far the spread across sectors and geographies goes. If what you want is a daily balance, this is the wrong tool. If what you want is to know whether three funds are the same bet three times over, that is what the free scan is for.Link to this answer

Yes — that is the one job PortLens is built for, and the scan is free and needs no account for up to 20 holdings; a free account lifts that cap. It replaces each fund with its constituent holdings, multiplies every company’s weight inside the fund by that fund’s share of your money, and sums the same company across every position you own, so a stock held through three funds and directly shows up once, at its real weight. When we have the fund’s SEC N-PORT filing, the scan uses every constituent that source publishes. Funds we have no holdings list for, including UCITS/LSE listings such as CSPX.L and VUSA.L that file no N-PORT, contribute no underlying companies. So each scan states the coverage ratio it reached rather than claiming to have opened everything, and the arithmetic and its limits are on the methodology page.Link to this answer

Yes. Hidden concentration is the gap between what your statement lists and what you own — ten fund lines can be close to one bet when the same mega-caps sit near the top of most of them. The free PortLens scan measures it in three numbers for up to 20 holdings with no account and more with a free account: your top-10 weight across the funds we have holdings lists for, how many of your funds each of those companies reaches you through, and effective holdings (1 ÷ the sum of squared weights), which says how many equally-weighted positions your portfolio actually behaves like — one 50% and two 25% positions behave like 2.7, not 3. Each scan also reports the coverage ratio behind those figures, and it is the number to read first: below roughly 75% coverage the concentration figures understate reality, because the funds that could not be looked through are the ones going uncounted.Link to this answer

Yes — the core scan is free and doesn’t require an account. Enter your holdings and you get true exposure, ETF overlap, hidden concentration, portfolio beta, and the diversification score, with coverage shown for the funds we have holdings lists for. Return projections start free too, with two models (CAPM and your own trailing history); Pro adds three more — Monte Carlo simulation, a macro model, and a Fama-French factor regression on your actual holdings. Portfolio data stays private: scans aren’t published anywhere, and competitions only ever share the stats you explicitly choose to share.Link to this answer

ETF holdings come from SEC N-PORT filings. Funds whose constituent lists cannot be resolved contribute no underlying companies to scan look-through. Fund expense ratios come from SEC prospectus data. Market prices come from Financial Modeling Prep, with Yahoo Finance as a fallback and CoinGecko for crypto; the risk-free rate is the 1-year yield from the US Treasury daily par curve; factor data is the daily Fama-French series from the Ken French Data Library. Featured investor portfolios come from SEC 13F filings. Every source, refresh schedule, and known limitation, including exactly where ETF constituent coverage is weakest, is documented on the methodology page.Link to this answer