{"url":"https://etfiq.com/academy/allocation-and-risk/overlap-hidden-concentration/","section":"academy","title":"Overlap and hidden concentration across your funds | ETFIQ","description":"Learn to find the companies you own several times over, across three ETFs, using real VOO, VUG and MGK holdings and ETFIQ's overlap tool.","as_of":"Sep 30, 2026","structured_data":[{"@type":"LearningResource","@id":"https://etfiq.com/academy/allocation-and-risk/overlap-hidden-concentration/#lesson","name":"Overlap and hidden concentration across your funds","description":"By holdings dated Sep 30, 2026, $10,000 split equally across VOO, VUG and MGK put 11.86% in NVIDIA, against 8.40% in VOO alone.","url":"https://etfiq.com/academy/allocation-and-risk/overlap-hidden-concentration/","learningResourceType":"Lesson","teaches":"Look-through weight: how holdings from several funds stack into one company","educationalLevel":"Intermediate","timeRequired":"PT7M","inLanguage":"en","isAccessibleForFree":true,"isPartOf":{"@type":"Course","@id":"https://etfiq.com/academy/allocation-and-risk/#course","name":"Allocation and Risk","url":"https://etfiq.com/academy/allocation-and-risk/"},"position":4,"dateModified":"2026-09-30","author":{"@type":"Organization","name":"ETFIQ Research","url":"https://etfiq.com"},"publisher":{"@type":"Organization","name":"ETFIQ Research","url":"https://etfiq.com"}},{"@type":"FAQPage","@id":"https://etfiq.com/academy/allocation-and-risk/overlap-hidden-concentration/#check","mainEntity":[{"@type":"Question","name":"You hold 50% in fund A, where a company is 10%, and 50% in fund B, where it is 4%. What is your look-through weight in that company?","acceptedAnswer":{"@type":"Answer","text":"7%. 50% \u00d7 10% + 50% \u00d7 4% = 5% + 2% = 7%."}},{"@type":"Question","name":"Two funds overlap by 87%. What does that tell you?","acceptedAnswer":{"@type":"Answer","text":"87% of their weight sits in the same securities. Overlap by weight counts money, not company names."}},{"@type":"Question","name":"Which number best shows how much one company's bad year could cost your whole portfolio?","acceptedAnswer":{"@type":"Answer","text":"The company's look-through weight across all your funds. It is the share of all your money in that company."}}]},{"@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"ETFIQ","item":"https://etfiq.com/"},{"@type":"ListItem","position":2,"name":"Academy","item":"https://etfiq.com/academy/"},{"@type":"ListItem","position":3,"name":"Allocation and Risk","item":"https://etfiq.com/academy/allocation-and-risk/"},{"@type":"ListItem","position":4,"name":"Overlap and hidden concentration acros","item":"https://etfiq.com/academy/allocation-and-risk/overlap-hidden-concentration/"}]},{"@type":"WebPage","name":"Overlap and hidden concentration across your funds","description":"Learn to find the companies you own several times over, across three ETFs, using real VOO, VUG and MGK holdings and ETFIQ's overlap tool.","url":"https://etfiq.com/academy/allocation-and-risk/overlap-hidden-concentration/","dateModified":"2026-09-30","isPartOf":{"@type":"WebSite","name":"ETFIQ","url":"https://etfiq.com"},"speakable":{"@type":"SpeakableSpecification","cssSelector":[".lede"]},"publisher":{"@id":"https://etfiq.com/#org"}}],"characters":6082,"truncated":false,"content":"ETFIQ / Academy / Allocation and Risk / Overlap and hidden concentration acros \n \n Overlap and hidden concentration across your funds\n Data as of Sep 30, 2026. Rebuilt every trading night.\n By holdings dated Sep 30, 2026 , $10,000 split equally across VOO, VUG and MGK put 11.86% in NVIDIA, against 8.40% in VOO alone.\n Allocation and Risk \u00b7 Lesson 4 of 7 1 2 3 4 5 6 7 \n Set an amount. See the dollars in NVIDIA and in the top three companies, one fund against three. Amount (hypothetical) $10,000 On $10,000: NVIDIA, all in VOO $840, NVIDIA, VOO + VUG + MGK in thirds $1,186, Top three, all in VOO $2,157, Top three, VOO + VUG + MGK in thirds $3,100. Hypothetical amounts, split in equal thirds. Weights from holdings dated Sep 30, 2026. Step 1: pairs. ETFIQ's overlap by weight: Step 2: one company, all three funds. Put $10,000 in equal thirds. NVIDIA's weight is 8.40% of VOO, 13.49% of VUG and 13.69% of MGK. With a third in each: Step 3: the top three together. Step 4: the same company under two tickers. Alphabet has two kinds of shares, GOOGL and GOOG. Overlap tools match securities, not companies, so Alphabet shows as two smaller lines and looks less important than it is. Add them: ( 3.07 + 5.16 + 4.98 ) \u00f7 3 = 4.40% plus ( 2.46 + 4.09 + 3.95 ) \u00f7 3 = 3.50% gives 7.90% in Alphabet, nearly as much as Microsoft. \n The question\n I hold three different funds with more than 600 holdings between them. Could most of my money still be riding on a few companies?\n The idea\n Beginner lesson 2 measured overlap by weight between two funds. With three or more funds, ask a sharper question: across everything I own, how much of my money sits in each company? That is your look-through weight .\n For one company, it adds up like this:\n look-through weight = for each fund, (your share in that fund \u00d7 the company's weight in it), added up\n Hidden concentration is a company that is modest in each fund but large in your total.\n Worked example\n The 4 steps beside the drawing at the top work this through on ETFIQ data. Point at a step to light the part of the drawing it describes.\n Three Vanguard funds, all with holdings dated Sep 30, 2026 :\n Fund What it holds Holdings Top 10 share \n VOO S&P 500 505 39.1% \n VUG US growth companies 135 63.1% \n MGK The largest growth companies 52 64.5% \n VOO and VUG: 58% \n VOO and MGK: 52% \n VUG and MGK: 87% \n VUG and MGK are nearly one fund. For three funds, the overlap tool takes the smallest of the three weights for each security, then adds them up: 52.2% is held by all three.\n ( 8.40% + 13.49% + 13.69% ) \u00f7 3 = 11.86% of your money\n That is $1,186 in one company. In VOO alone, it would be $840 .\n Company VOO VUG MGK Your look-through weight \n NVIDIA 8.40% 13.49% 13.69% 11.86% \n Apple 7.39% 12.51% 12.53% 10.81% \n Microsoft 5.79% 9.75% 9.46% 8.33% \n Top three 21.6% 35.7% 35.7% 31.0% \n Almost a third of the money rides on three companies. Adding two growth funds to VOO did not spread the money. It stacked it on the companies all three already favoured.\n The common mistake\n \"Different fund names, different strategies, so I'm spread out.\" Growth funds and the S&P 500 can lead with the same handful of giant companies, as these three did. The labels differ; the top holdings don't.\n A second mistake is stopping at pairs. Overlap between two funds says nothing about how your weights stack. Only the look-through weight tells you what one company's bad year would cost you.\n Check your understanding\n Pick an answer to see why. Two of three right passes the lesson.\n 1. You hold 50% in fund A, where a company is 10%, and 50% in fund B, where it is 4%. What is your look-through weight in that company? A 14% B 10% C 7% D 4% Answer: C. 7%. 50% \u00d7 10% + 50% \u00d7 4% = 5% + 2% = 7%. Not A: adding the two weights ignores that each fund holds only half your money. 2. Two funds overlap by 87% . What does that tell you? A 87% of their companies are the same B They returned 87% of the same amount C You own 87% of each D 87% of their weight sits in the same securities Answer: D. 87% of their weight sits in the same securities. Overlap by weight counts money, not company names. Not A: a fund can share many small names and little money, or the reverse. 3. Which number best shows how much one company's bad year could cost your whole portfolio? A How many funds you hold B The company's look-through weight across all your funds C The overlap between your two largest funds D The company's weight in your largest fund Answer: B. The company's look-through weight across all your funds. It is the share of all your money in that company. Not D: one fund's weight misses what the other funds add. \n Takeaways\n Work out your look-through weight in your five largest companies, across every fund you own. \n Pairwise overlap is the first check; the look-through total is the one that measures your risk. \n Add up share classes of one company, like GOOGL and GOOG, before you judge your spread. \n Do it on ETFIQ\n Put all the funds you own into the overlap tool \n Where to next\n Next lesson: Core and satellite: where theme funds fit Previous lesson: Allocation funds: what a stock-share band tells you Allocation and Risk: all lessons The explainer behind this lesson ETFIQ Academy How ETFIQ computes these numbers \n Cite this page. ETFIQ, Overlap and hidden concentration across your funds, data as of Sep 30, 2026. https://etfiq.com/academy/allocation-and-risk/overlap-hidden-concentration/ Free to use with attribution for data ETFIQ computes; issuer data stays under its owner's terms. The underlying files are at Open data .\n Other forms Plain ETFIQ, Overlap and hidden concentration across your funds, data as of Sep 30, 2026. https://etfiq.com/academy/allocation-and-risk/overlap-hidden-concentration/ APA ETFIQ. (Sep 30, 2026). Overlap and hidden concentration across your funds. Retrieved from https://etfiq.com/academy/allocation-and-risk/overlap-hidden-concentration/ Markdown [Overlap and hidden concentration across your funds (ETFIQ, Sep 30, 2026)](https://etfiq.com/academy/allocation-and-risk/overlap-hidden-concentration/)","source":"ETFIQ, independent ETF data. Recomputed nightly from public filings and prices.","publisher":{"@id":"https://etfiq.com/#org","name":"ETFIQ","url":"https://etfiq.com"},"license":"https://etfiq.com/license/","license_text":"Data ETFIQ computes is free to use with attribution: ETFIQ (etfiq.com). Issuer data stays under its owner's terms.","citation":"ETFIQ, Overlap and hidden concentration across your funds, data as of Sep 30, 2026. https://etfiq.com/academy/allocation-and-risk/overlap-hidden-concentration/"}