Key Takeaways
- The cost of a fee splits into two parts that behave differently: the fee dollars paid, and the compounding those dollars never produced. Only the first appears on a statement.
- The split is not an estimate. Subtracting the fee-paying balance from the fee-free one gives an exact identity: the shortfall equals each year's fee compounded forward at the gross return for the years it would still have been invested.
- The crossover comes in year 24 on these assumptions. Before then most of the shortfall is fees; after then most of it is growth that never happened.
- Dollar cost rises faster than the horizon. Going from 20 years to 40 multiplies the cost by 7.03, not by two, because the base the fee is charged on is itself compounding.
- Dollar cost rises slightly slower than the fee rate. Doubling a 0.50% fee to 1.00% raises the 30-year cost by a factor of 1.86, not 2.00.
- A fee is charged on the balance, not the gain. A fee numerically equal to the return still loses money, by exactly the starting balance times the return times the fee.
- In a withdrawal phase the spending plan does not change, so the fee lands entirely on what is left, or on the date the money runs out.
- None of this says whether a fee is worth paying. The model holds the gross return fixed on purpose, which isolates cost and deliberately ignores everything a fee might buy.
Assumptions Behind Every Number on This Page
Every figure on this page is reproducible from the list below. There are no hidden parameters, no historical data set and no fitted model.
- Gross return. A constant 7.00% a year in the accumulation tables, before fees and before tax. Constant, not average: returns arrive in the same size every year.
- Compounding. Annual. One period per year, no intra-year compounding.
- Contribution timing. At the start of the year, before that year's growth.
- Fee timing. At the end of the year, assessed on the balance after growth. Real expense ratios accrue daily against net asset value and real advisory fees are usually billed quarterly on an average balance, so an end-of-year assessment charges on a slightly larger base. These figures are therefore a modest upper bound on the annual-accrual case rather than a match for any particular fee schedule.
- Scenario A. A single $100,000 investment with no further contributions.
- Scenario B. $10,000 invested at the start of every year, starting from nothing.
- Fee levels. 0.05%, 0.50%, 1.00% and 1.05%, chosen to span a broad-index fund expense ratio, a mid-cost fund, a common advisory fee, and an advisory fee layered on top of a fund expense ratio.
- Horizons. 10, 20, 30 and 40 years.
- Withdrawal scenario. $1,000,000 at a constant 5.00% gross return, $40,000 withdrawn at the start of year one and increased 2.50% a year, over 30 years.
- Currency and tax. Nominal US dollars. No tax of any kind is modeled, in any account type.
The arithmetic lives in one pure module, public/fee-compounding-core.js, with no browser or network dependency. The tables below are written into this page by a generator that imports that module, so a published figure and the code that produced it cannot drift apart. The same module runs the calculator further down the page and answers the machine-readable tool this page exposes to browser agents.
Why Is the Total Cost of a Fee Larger Than the Fees Paid?
Because a fee dollar is removed and then never earns again. Write the two balances as recurrences, with A for the fee-free baseline, B for the fee-paying portfolio, C for the annual contribution, g for the gross return and f for the fee rate:
- At = (At-1 + C) times (1 + g)
- Bt = (Bt-1 + C) times (1 + g) times (1 - f)
- feet = (Bt-1 + C) times (1 + g) times f
Subtract the second from the first. The contribution cancels, and what is left is a clean statement about the gap Dt = At - Bt:
Dt = Dt-1 times (1 + g) plus feet
Unroll that from D0 = 0 and the gap at the horizon N is the sum of every year's fee compounded forward at the gross return for the years it would still have been invested:
DN = sum over t of feet times (1 + g) to the power (N - t)
Split the bracket and the two named quantities in this study fall out. Fees paid is the sum of feet. Foregone compounding is the sum of feet times [(1 + g) to the power (N - t), minus 1]. The second term is the number almost nobody publishes, and it is not a residual estimate: it is an identity. The calculation module computes it both ways, as a residual and as the closed-form sum, and the unit tests assert the two agree.
One consequence is worth stating plainly. The foregone half depends on the gross return, not on the fee. A higher assumed return makes a fee more expensive, not less, because the money the fee took away would have grown faster.
Results: A Single Lump-Sum Investment
The first scenario is the cleanest possible test of the arithmetic: one investment, no contributions, one constant return, one fee. Read the last column as the share of the fee-free outcome that the fee consumed.
| Annual fee | Years | Ends with, no fee | Ends with, after fee | Fees paid | Foregone compounding | Total cost | Share of fee-free result |
|---|---|---|---|---|---|---|---|
| 0.05% | 10 | $196,715 | $195,734 | $737 | $244 | $981 | 0.50% |
| 0.05% | 20 | $386,968 | $383,117 | $2,180 | $1,671 | $3,851 | 1.00% |
| 0.05% | 30 | $761,226 | $749,890 | $5,005 | $6,331 | $11,336 | 1.49% |
| 0.05% | 40 | $1,497,446 | $1,467,787 | $10,534 | $19,124 | $29,659 | 1.98% |
| 0.50% | 10 | $196,715 | $187,098 | $7,208 | $2,410 | $9,617 | 4.89% |
| 0.50% | 20 | $386,968 | $350,056 | $20,693 | $16,220 | $36,913 | 9.54% |
| 0.50% | 30 | $761,226 | $654,946 | $45,924 | $60,355 | $106,279 | 13.96% |
| 0.50% | 40 | $1,497,446 | $1,225,390 | $93,130 | $178,926 | $272,056 | 18.17% |
| 1.00% | 10 | $196,715 | $177,906 | $14,057 | $4,752 | $18,809 | 9.56% |
| 1.00% | 20 | $386,968 | $316,504 | $39,066 | $31,399 | $70,464 | 18.21% |
| 1.00% | 30 | $761,226 | $563,079 | $83,557 | $114,589 | $198,147 | 26.03% |
| 1.00% | 40 | $1,497,446 | $1,001,749 | $162,710 | $332,987 | $495,697 | 33.10% |
| 1.05% | 10 | $196,715 | $177,009 | $14,723 | $4,983 | $19,706 | 10.02% |
| 1.05% | 20 | $386,968 | $313,322 | $40,784 | $32,862 | $73,646 | 19.03% |
| 1.05% | 30 | $761,226 | $554,609 | $86,915 | $119,701 | $206,616 | 27.14% |
| 1.05% | 40 | $1,497,446 | $981,710 | $168,570 | $347,166 | $515,736 | 34.44% |
Total cost is the gap against an identical fee-free portfolio, not the fees paid.
Two features of that grid are worth naming. First, at every fee level the share of the fee-free result that the fee consumes roughly doubles from 10 years to 20 years, is close to three times the 10-year figure by year 30, and keeps climbing after that, even though the fee rate never changes. Second, the foregone-compounding column overtakes the fees-paid column somewhere between 20 and 30 years at every fee level, which means a cost quoted as fees paid is progressively more misleading the longer the horizon it describes.
At the extremes of the grid, a 0.05% expense ratio costs $29,659 over 40 years while a 1.00% fee costs $495,697 on the same portfolio. Neither figure is a prediction. Both follow from the assumptions listed above and nothing else.
Results: A Regular Contribution Schedule
Most portfolios are built by contributing rather than by a single deposit, and the shape of the answer changes. Money contributed in year 35 has only five years to be charged on, so a contributing investor's fee burden is weighted toward the early money and the foregone-compounding share grows more slowly.
| Annual fee | Years | Ends with, no fee | Ends with, after fee | Fees paid | Foregone compounding | Total cost | Share of fee-free result |
|---|---|---|---|---|---|---|---|
| 0.05% | 10 | $147,836 | $147,389 | $365 | $82 | $447 | 0.30% |
| 0.05% | 20 | $438,652 | $435,880 | $1,817 | $955 | $2,772 | 0.63% |
| 0.05% | 30 | $1,010,730 | $1,000,553 | $5,395 | $4,782 | $10,177 | 1.01% |
| 0.05% | 40 | $2,136,096 | $2,105,809 | $13,138 | $17,149 | $30,287 | 1.42% |
| 0.50% | 10 | $147,836 | $143,432 | $3,594 | $810 | $4,404 | 2.98% |
| 0.50% | 20 | $438,652 | $411,789 | $17,526 | $9,336 | $26,862 | 6.12% |
| 0.50% | 30 | $1,010,730 | $913,880 | $50,801 | $46,049 | $96,850 | 9.58% |
| 0.50% | 40 | $2,136,096 | $1,853,281 | $120,264 | $162,550 | $282,814 | 13.24% |
| 1.00% | 10 | $147,836 | $139,166 | $7,067 | $1,603 | $8,670 | 5.86% |
| 1.00% | 20 | $438,652 | $386,750 | $33,697 | $18,205 | $51,902 | 11.83% |
| 1.00% | 30 | $1,010,730 | $827,216 | $95,130 | $88,384 | $183,514 | 18.16% |
| 1.00% | 40 | $2,136,096 | $1,610,831 | $218,480 | $306,784 | $525,265 | 24.59% |
| 1.05% | 10 | $147,836 | $138,747 | $7,408 | $1,681 | $9,089 | 6.15% |
| 1.05% | 20 | $438,652 | $384,342 | $35,243 | $19,067 | $54,310 | 12.38% |
| 1.05% | 30 | $1,010,730 | $819,067 | $99,238 | $92,426 | $191,664 | 18.96% |
| 1.05% | 40 | $2,136,096 | $1,588,570 | $227,237 | $320,288 | $547,525 | 25.63% |
Same arithmetic as Scenario A, with the balance built by contributions rather than a single deposit.
Over 40 years of $10,000 annual contributions, totalling $400,000 invested, a 1.00% fee costs $525,265. That is more than the entire sum contributed. Of it, $218,480 is fees paid and $306,784 is foregone compounding, a foregone share of 58.4% against 67.2% in the lump-sum case. Later contributions dilute the compounding effect without removing it.
How Does the Cost Split Between Fees Paid and Foregone Compounding?
The split moves steadily in one direction. This is the same 1.00% lump-sum run, opened up year by year.
| Year | No fee | After fee | Fees to date | Foregone compounding | Foregone share of the gap |
|---|---|---|---|---|---|
| 1 | $107,000 | $105,930 | $1,070 | $0 | 0.0% |
| 5 | $140,255 | $133,381 | $6,023 | $851 | 12.4% |
| 10 | $196,715 | $177,906 | $14,057 | $4,752 | 25.3% |
| 15 | $275,903 | $237,293 | $24,773 | $13,837 | 35.8% |
| 20 | $386,968 | $316,504 | $39,066 | $31,399 | 44.6% |
| 24 | $507,237 | $398,525 | $53,865 | $54,847 | 50.5% |
| 25 | $542,743 | $422,157 | $58,130 | $62,456 | 51.8% |
| 30 | $761,226 | $563,079 | $83,557 | $114,589 | 57.8% |
| 35 | $1,067,658 | $751,042 | $117,473 | $199,144 | 62.9% |
| 40 | $1,497,446 | $1,001,749 | $162,710 | $332,987 | 67.2% |
Sampled at five-year intervals, plus the crossover year and the final year.
In year one the foregone half is zero by construction: a fee charged at the end of the final year has no time left to compound. It climbs from there, passes half the total in year 24, and reaches 67.2% by year 40. Anyone quoting a long-horizon fee cost as the sum of the fees is therefore reporting roughly a third of it.
Why Is a Fee Charged on the Balance Rather Than the Gain?
Because that is what the fee is defined as. A fund expense ratio is the fund's own operating cost expressed as a percentage of net assets, deducted from net asset value whether or not the fund made money. An advisory fee is a charge for managing assets, quoted as a percentage of assets under management. Neither is a share of profit, and neither is contingent on there being a profit.
Two consequences follow, and both are visible in the arithmetic rather than being matters of opinion.
The fee is owed in losing years. A $100,000 portfolio that returns minus 5% falls to $95,000, then pays $950 at a 1.00% fee, ending at $94,050. The fee shrinks in dollars because the balance shrank, but it does not go away.
A fee equal to the return still loses money. At a 7.00% return and a 7.00% fee, $100,000 grows to $107,000 and the fee then takes 7% of that larger number, leaving $99,510. The $490 shortfall is exactly the starting balance times the return times the fee. That product is the whole reason a percentage-of-balance charge is not the mirror image of a percentage-of-gain charge: the fee is levied on the grown balance, while the growth was earned only on the starting balance.
The same arithmetic explains the net rate this study reports. A 7.00% gross return with a 1.00% fee does not net 5.93% by coincidence: (1 + g)(1 - f) - 1 is g minus f minus their product, so the net rate is a hair below the naive subtraction of 6.00%.
Why Is Fee Drag Roughly Linear in the Fee Rate but Superlinear in Time?
Total cost in this model is the fee-free terminal value multiplied by one minus (1 - f) raised to the power N. Each variable enters that expression differently.
In the fee rate, close to linear and slightly under. At a fixed horizon the bracket is approximately N times f for small f, so doubling the fee roughly doubles the cost. It falls a little short because a larger fee shrinks the balance the later fees are charged against. Over 30 years on these assumptions, a 0.50% fee costs $106,279 and a 1.00% fee costs $198,147, a ratio of 1.86. Treating twice the fee as twice the cost is a fair first approximation and errs on the pessimistic side.
In time, decisively superlinear in dollars. The fee-free terminal value is itself compounding, so the base the percentage bites into grows exponentially while the percentage bitten also rises. On these assumptions a 1.00% fee costs $18,809 over 10 years, $70,464 over 20, $198,147 over 30 and $495,697 over 40. Doubling the horizon from 20 years to 40 multiplies the cost by 7.03.
The practical reading of those two facts together: a fee decision is far more sensitive to how long the money will be invested than to how large the fee is. A negotiation that halves a fee is worth less than a decision that was made twenty years earlier.
How Do a Fund Expense Ratio and an Advisory Fee Combine?
They stack against one balance, so the exact combined rate is one minus the product of the surviving fractions rather than the simple sum. The difference is the cross term, and it is small.
| Fund expense ratio | Advisory fee | Sum of the two | Exact combined rate | Cross term |
|---|---|---|---|---|
| 0.03% | 0.25% | 0.28% | 0.2799% | 0.0001 pp |
| 0.05% | 1.00% | 1.05% | 1.0495% | 0.0005 pp |
| 0.20% | 1.00% | 1.20% | 1.1980% | 0.0020 pp |
| 0.50% | 1.00% | 1.50% | 1.4950% | 0.0050 pp |
| 1.00% | 1.00% | 2.00% | 1.9900% | 0.0100 pp |
The exact combined rate is one minus the product of the surviving fractions. The cross term is what adding the two rates overstates, in percentage points.
A 0.05% expense ratio alongside a 1.00% advisory fee adds to 1.05% and combines exactly to 1.0495%, a gap of 0.0005 percentage points. Adding fee layers together overstates the true rate by that cross term, which is why the industry convention of quoting an all-in fee as a sum is safe: it is conservative, and the error is invisible next to the uncertainty in any return assumption. The convention stops being harmless only at fee levels far above anything a retail investor should be paying.
What is not harmless is failing to add the layers at all. A fund expense ratio is deducted inside the fund and never appears on an account statement, while an advisory fee usually does. Reading only the statement makes a 1.05% all-in cost look like a 1.00% one.
What Does a Fee Do During a Withdrawal Phase?
Accumulation and decumulation are not symmetric. During accumulation a fee reduces a number that will not be spent for decades. During withdrawal the portfolio is shrinking anyway, and the fee competes directly with the spending it is meant to fund. The first table holds the spending plan constant across every fee level, so the entire effect lands on what is left at the end.
| Annual fee | Total withdrawn | Fees paid | Balance after 30 years | Money runs out |
|---|---|---|---|---|
| 0.00% | $1,756,108 | $0 | $584,993 | Lasted the horizon |
| 0.05% | $1,756,108 | $13,889 | $552,772 | Lasted the horizon |
| 0.50% | $1,756,108 | $122,570 | $288,655 | Lasted the horizon |
| 1.00% | $1,756,108 | $212,791 | $44,390 | Lasted the horizon |
| 1.50% | $1,608,021 | $279,601 | $0 | Year 29 |
The same total was spent in every row the portfolio could fund. What differs is the ending balance: $584,993 with no fee against $44,390 at a 1.00% fee, on $212,791 of fees paid. At a 1.50% fee the plan stops being fundable before the horizon ends.
Where the withdrawal rate is already beyond what the portfolio can sustain, the fee changes the date rather than the balance. The second table raises the first-year withdrawal to $60,000 and lets each run go until the money is gone.
| Annual fee | Money runs out | Total withdrawn | Spending the fee left unfunded |
|---|---|---|---|
| 0.00% | Year 21 | $1,628,980 | $0 |
| 0.50% | Year 20 | $1,516,398 | $112,583 |
| 1.00% | Year 19 | $1,421,517 | $207,464 |
| 1.50% | Year 18 | $1,340,194 | $288,787 |
The withdrawal plan is identical in every row. A run is treated as depleted the first year it cannot pay the full planned withdrawal.
The fee-free portfolio runs out in year 21 and the 1.00% portfolio in year 19, funding $207,464 less spending along the way. Two years is the whole of the fee's effect stated in the unit that matters to someone drawing an income, and it is a far more legible number than a percentage.
One caution specific to this section. A constant return assumption removes sequence risk entirely, and sequence risk is the dominant danger in a withdrawal phase. A real portfolio drawing income through an early drawdown can fail years sooner than any constant-return model predicts. Use the sequence-of-returns simulator for that question; this page is not the right instrument for it.
Run the Study on Your Own Numbers
The same calculation module that produced every table above runs here. Choose a phase, replace the assumptions with your own, and the results update. Nothing is transmitted anywhere and nothing is stored between visits.
A modeled illustration on the figures entered above, not a forecast. A single constant return is applied every year, so there is no sequence risk in this result. No tax of any kind is modeled.
Result
Year by year
| Year | No fee | After fee | Fee that year | Fees to date | Foregone compounding |
|---|
Long horizons are summarised at five-year intervals plus the final year.
What This Arithmetic Does Not Capture
The model is deliberately narrow, and reading it as more than it is would be a mistake. Five omissions matter most.
- Taxes. Nothing here is after tax. Fees charged inside a fund reduce taxable distributions, an advisory fee billed on a taxable account is generally not deductible under current federal rules, and the same fee produces different after-tax outcomes in a taxable account and a tax-deferred one. Tax treatment is a question for a qualified tax professional, not for this page.
- Sequence risk. A single constant return is the whole point of the model and also its largest simplification. Real returns arrive unevenly, and the order in which they arrive changes outcomes materially even when the average is identical. That effect is largest exactly where this page's withdrawal section looks most confident.
- What the fee buys. The gross return is held identical across every fee level so the only variable is cost. That is what makes the comparison clean and what makes it incomplete. A fee that buys real diversification, tax management, rebalancing discipline, or advice that keeps someone invested through a drawdown may be worth more than it costs. This arithmetic sizes the hurdle; it cannot tell you whether the hurdle was cleared.
- Other real costs. Bid-ask spreads, brokerage commissions, cash drag, a fund's tracking difference against its benchmark, transaction-based charges and performance fees are all outside the model. The all-in cost of owning a fund is usually higher than its expense ratio, which is the subject of expense ratios and the total cost of ETF ownership.
- Inflation. Every figure is nominal. In real terms both the fee-free and the fee-paying outcomes are smaller, and the ratio between them is unchanged, so the percentages survive the translation while the dollar amounts do not.
One further limit is procedural rather than mathematical. Fee schedules change, breakpoints reduce advisory rates above certain asset levels, and share classes within a single fund can carry materially different expense ratios. A rate that is correct today is an assumption about tomorrow.
Where This Sits Among Swoopr Investment's Other Fee Tools
Three pages on this site cover cost, from different angles, and they are deliberately not merged.
- Expense Ratios and Total Cost of ETF Ownership is the guide to what an ETF actually costs: the headline expense ratio plus spread, tracking difference and securities lending offsets. Start there if the question is which fund is genuinely cheaper.
- The Investment Fee Drag Calculator compares two to five fee levels side by side on one set of assumptions and reports the ending gap for each. Use it to price a specific choice between named options.
- This page is the study behind both: one fee, decomposed, across horizons and phases, with the arithmetic shown and the foregone-compounding half separated out. Use it when the question is why the number behaves the way it does.
For the growth side of the same equation without any fee at all, the compound growth calculator projects a balance forward on a stated return.
Frequently Asked Questions
How much does a 1% investment fee cost over 30 years?
On the assumptions used throughout this study, a single $100,000 investment growing at a constant 7% gross annual return ends 30 years later at $761,226 with no fee and $563,079 after a 1.00% annual fee. The shortfall is $198,147, of which $83,557 is fee dollars actually paid and $114,589 is growth those dollars would have produced had they stayed invested. That is a modeled illustration from stated assumptions, not a forecast, and it excludes taxes entirely.
Why is the total cost of a fee larger than the fees paid?
Because a fee dollar removed in year three is not only gone, it also stops earning. Every subsequent year of growth is applied to a smaller balance. Writing the fee-free and fee-paying balances as two recurrences and subtracting them shows the gap at the horizon equals the sum of each year's fee compounded forward at the gross return for the years it would still have been invested. Split that sum in two and the first part is the fees themselves, the second part is the growth given up on them.
Is investment fee drag linear in the fee rate?
Almost, and slightly less than proportional. Doubling the fee does not quite double the dollar cost, because the higher fee shrinks the balance that later fees are charged against. On the study assumptions over 30 years, a 1.00% fee costs $198,147 against $106,279 for a 0.50% fee, a ratio of 1.86 rather than 2.00. The rule of thumb that twice the fee costs roughly twice as much is close enough for a first pass and slightly pessimistic.
Why is a fee charged on my whole balance instead of on my gains?
Because an expense ratio is an operating cost of the fund and an advisory fee is a charge for managing assets, and both are defined as a percentage of assets under management rather than a share of profit. The consequence is that the fee is owed in years when the portfolio loses money, and that a fee numerically equal to the return still loses money: the fee is levied on the whole grown balance while the growth was earned only on the starting balance.
What happens if the fee is as large as the return?
The portfolio shrinks rather than standing still. With a 7% gross return and a 7% annual fee, $100,000 grows to $107,000 and the fee then takes 7% of that larger figure, leaving $99,510. The $490 shortfall is exactly the starting balance multiplied by the return and then by the fee. A fee equal to the return is therefore worse than break-even by the product of the two rates, every year.
Does a fee still get charged when the market falls?
Yes. An asset-based fee is charged on whatever the balance is, so a losing year produces a smaller fee in dollars but not no fee. In this model a $100,000 portfolio that returns minus 5% falls to $95,000 and then pays $950 on a 1.00% fee, ending at $94,050. Over a long run of negative returns the arithmetic reverses in one respect: money removed early would itself have shrunk, so the fee dollars slightly overstate the true cost.
How do a fund expense ratio and an advisory fee combine?
They are charged against the same balance, so the exact combined rate is one minus the product of the two surviving fractions, not the simple sum. A 0.05% expense ratio alongside a 1.00% advisory fee adds to 1.05% and combines exactly to 1.0495%, a difference of 0.0005 percentage points. Adding fee layers together overstates the combined rate by a cross term small enough to ignore at realistic fee levels, which is why the industry convention of adding them is safe.
Does a fee matter during retirement withdrawals?
It matters more, because the portfolio is being drawn down at the same time. On this study's withdrawal assumptions the spending plan is identical in every row, so the fee shows up entirely in what is left at the end: $584,993 with no fee against $44,390 at a 1.00% fee after 30 years. Where the withdrawal rate is already too high, the fee moves the date the money runs out forward rather than reducing a final balance.
At what point does foregone compounding exceed the fees paid?
In year 24 on this study's assumptions, for a single $100,000 investment at a 7% gross return paying a 1.00% annual fee. Before that point most of the shortfall is fee dollars. After it, most of the shortfall is growth that never happened. By year 40 the growth given up is 67.2% of the total, which is why quoting only the fees paid understates the cost of a long-horizon fee by roughly a factor of three.
Does this study account for taxes?
No, and that omission cuts both ways. Fees paid inside a fund reduce taxable distributions, and an advisory fee billed on a taxable account is generally not deductible under current federal rules, so the after-tax cost of a fee is not simply the pre-tax cost. Account type matters too: the same fee in a tax-deferred account and a taxable account produces different after-tax outcomes. Anything tax-specific belongs with a qualified tax professional.
Does a lower fee always mean a better outcome?
No. This arithmetic holds the gross return fixed across every fee level so the only thing that varies is cost, which is exactly what makes the comparison clean and exactly what makes it incomplete. A fee can buy diversification, tax management, rebalancing discipline, or advice that keeps someone invested through a drawdown they would otherwise have sold into. None of that is visible in the model. What the model does establish is the size of the hurdle the fee has to clear.
Are these numbers a forecast of what my portfolio will do?
No. Every figure here is a modeled illustration produced by applying a single constant return assumption to a stated starting balance and contribution schedule. Real returns arrive in an uneven sequence, which changes outcomes materially even when the average is identical, and no return assumption is a prediction. The purpose of the study is to isolate the shape of fee arithmetic, not to project any particular portfolio.
References
- SEC: Investor Bulletin: How Fees and Expenses Affect Your Investment Portfolio
- SEC: Mutual Funds and ETFs: A Guide for Investors
- FINRA: Fund Analyzer
- Investor.gov: Mutual Fund and ETF Fees and Expenses
- Investor.gov: Compound Interest Calculator
Every source above was retrieved and its document title confirmed on 24 August 2026. Those sources establish that asset-based fees exist, how they are disclosed and that they reduce returns over time. They are not the source of any figure on this page: every number here is Swoopr Investment's own calculation from the assumptions stated above, produced by public/fee-compounding-core.js and checked against hand-worked values in tests/unit/fee-compounding-core.test.mjs. Fee schedules, share classes and disclosure rules change, so a rate taken from any source should be re-checked against the current version before it is relied on.