// Learn · Data & tools
Cross-tracker: how many times do you own the same stock?
Holding three ETFs is not the same as holding three portfolios. A World fund, an S&P 500 and a Nasdaq-100 are largely the same companies bought three times, and the top ten end up weighing far more than anyone intends. This looks through every fund in your plan and tells you which companies you hold more than once, and what each one really weighs. Computed in your browser, nothing is sent anywhere.
Your plan
Add the ETFs you hold, or plan to hold, and how much of the monthly contribution goes into each. Weights are rescaled to 100%, so rough numbers are fine.
Or start from a plan people actually hold:
Add at least one ETF with a weight above zero.
The holdings dataset could not be loaded. It ships with the site, so this usually means a network problem. The rest of the tools work offline: try the PAC simulator.
The companies you hold twice
Effective weight is what the company actually weighs in your whole plan, adding up every fund it appears in. That is the number that matters, not the weight it has inside any single ETF. Every duplicated company is listed, not a top ten: the tail is where the surprise usually is.
Where the money actually sits
The same look-through, grouped. Sector and country weights are computed on the part of your plan the dataset resolves into companies, so they describe the visible portfolio, not the whole one. A plan that felt global often turns out to be one sector in one country.
Fund against fund
For each pair, the share of the smaller position that is literally already inside the other fund. Measured by weight, not by counting names in common: two funds can share four hundred companies that weigh nothing, or seven that weigh a third of the portfolio.
All three exports carry the whole analysis, not just the table on screen: the funds with their weights and TER, the summary, every company with its sector, country, effective weight and the euro amount behind it, then sectors, countries and fund pairs. The CSV is for a spreadsheet, with English column names and dots as decimal separators. The report is Markdown, in your language, ready to paste into notes or into a chat to reason about it. The link carries the plan in the address itself, nothing is stored on any server.
Why duplication is not automatically bad
Owning Nvidia through three funds is not a mistake in itself. The mistake is not knowing you do. Overlap becomes a problem in two ways: the concentration is larger than you decided, so a single company's bad year hits harder than your plan assumed; and you are paying a second and third management fee for exposure you already had. If the same result comes from one broad fund at a lower cost, the extra funds are buying complexity, not diversification.
How it is computed, and what it cannot see
Companies are matched by ISIN, not by name or ticker. The same company listed on two exchanges has different tickers and differently spelled names but a single ISIN, so matching any other way would quietly split it into two and hide the duplication. Effective weight is the fund's weight in your plan multiplied by the company's weight inside the fund, summed across funds. Pairwise overlap is the sum of the smaller of the two weights for every shared company.
What it cannot see: anything outside the dataset. Coverage tells you how much of your plan's weight was actually resolved into companies, and the rest is invisible to the calculation. So every figure here is a lower bound. Fund compositions also change continuously, and this dataset is a snapshot, not a live feed.
Educational tool, not financial advice, and not a recommendation of any fund. Holdings data is a snapshot and may be estimated, incomplete or out of date, verify against the issuer's own documents before acting on anything here. Do your own research and consider a licensed advisor.