Time-Weighted vs Money-Weighted Returns: Which Performance Number Is Yours?

Time-Weighted vs Money-Weighted Returns: Which Performance Number Is Yours?

A portfolio can report one return while the investor experiences another. The difference often comes from cash-flow timing. Time-weighted return isolates how the investments performed; money-weighted return measures the result of both investment performance and when capital entered or left.

বাংলায় পড়ুন: Time-Weighted বনাম Money-Weighted Return: কোন Performance Number আপনার?

Learning objective: By the end of this tutorial, you should be able to calculate a simple time-weighted return, interpret an internal rate of return, explain why deposits and withdrawals change the investor's experience and choose the appropriate measure for a performance question.

1. Two measures, two questions

Time-weighted return (TWR)

TWR answers:

How did the portfolio strategy perform, independent of external deposits and withdrawals?

It breaks the measurement period at each material external cash flow, calculates the return for each sub-period and geometrically links those returns.

Money-weighted return (MWR)

MWR answers:

What return did the invested money experience, considering the amount and timing of cash flows?

An internal rate of return (IRR) is a common money-weighted measure. It finds the discount rate that makes the present value of contributions, withdrawals and the ending value equal to zero.

Neither number is automatically more honest. They measure different things.

2. A worked example

Assume two one-year sub-periods:

1. An investor starts with £10,000.
2. The portfolio gains 10% in year one, reaching £11,000.
3. The investor then adds £9,000, taking the account to £20,000.
4. The portfolio loses 10% in year two, ending at £18,000.

The investor contributed £19,000 in total and finished with £18,000—a cash loss of £1,000. Yet the portfolio's two sub-period returns were +10% and −10%.

3. Calculate the time-weighted return

Remove the effect of the £9,000 deposit by calculating each period separately:

• Year one return: +10%.
• Year two return: −10%.

Then link the growth factors:

TWR = (1 + 0.10) × (1 − 0.10) − 1 = −1%.

Over the two years, the strategy's time-weighted return is −1%. Annualised:

Annualised TWR = √0.99 − 1 ≈ −0.50% per year.

The £9,000 deposit does not improve or damage the TWR because it was an external client decision, not an investment return.

4. Calculate the money-weighted return

Write the investor's cash flows from the investor's perspective:

Time	Cash flow
Start	−£10,000 contribution
End of year one	−£9,000 contribution
End of year two	+£18,000 ending value

The annual IRR solves:

−£10,000 − £9,000 ÷ (1 + r) + £18,000 ÷ (1 + r)² = 0.

The solution is approximately:

Money-weighted return = −3.49% per year.

This is worse than the annualised TWR because more capital was exposed during the losing second year. The strategy return and the investor return differ because the deposit arrived before the weaker period.

5. Change the timing and the story changes

Now reverse the sub-period returns while keeping the same starting capital and deposit timing:

1. £10,000 loses 10%, falling to £9,000.
2. The investor adds £9,000, taking the account to £18,000.
3. The account gains 10%, ending at £19,800.

The time-weighted return is still:

0.90 × 1.10 − 1 = −1%.

The same strategy returns appear in a different order, so TWR is unchanged. But the investor now had more money exposed to the winning period and ends £800 above total contributions. The money-weighted result improves.

Cash-flow timing can therefore separate “how the portfolio performed” from “how my pounds performed”.

6. Why investment managers often report TWR

The GIPS Standards Handbook explains that TWR seeks to neutralise external cash flows that are generally client-driven. This helps evaluate a manager's ability to run a mandate without rewarding or penalising the manager for a client's decision to add or withdraw money.

For a true TWR:

1. Value the portfolio immediately before a material external cash flow.
2. Calculate each sub-period return.
3. Convert each return to a growth factor.
4. Multiply the growth factors.
5. Subtract one.

Daily valuation makes this easier. With less frequent valuation, methods such as Modified Dietz may estimate the cash-flow-adjusted return, but timing assumptions can introduce error.

7. When MWR may be more informative

MWR is useful when the investor or manager controls the timing and size of capital deployment. Examples include:

• a private-equity or venture-capital fund calling and distributing capital;
• a property project with staged investment and sale proceeds;
• a trader deliberately scaling capital as opportunities change;
• an individual's actual account experience with regular contributions;
• a strategy where holding cash is part of the investment decision.

GIPS generally requires TWR for comparable manager reporting, but permits MWR in specified circumstances, including certain closed-end, fixed-life, fixed-commitment or significantly illiquid strategies where the firm controls external cash flows.

The choice should follow the question and the degree of control over cash-flow timing.

8. IRR and XIRR are not interchangeable labels

IRR

Standard IRR usually assumes equally spaced periods. Monthly cash flows are treated as monthly intervals; annual cash flows as annual intervals.

XIRR

XIRR uses actual calendar dates and is more appropriate for irregular cash flows. A contribution on 2 January and another on 20 September should not be treated as evenly spaced.

Spreadsheet sign convention matters:

• Contributions from the investor are usually negative.
• Withdrawals, distributions and ending value are positive.
• At least one negative and one positive cash flow are required.

Some cash-flow patterns can produce more than one mathematical IRR or no meaningful solution. Do not accept a spreadsheet output without reviewing the cash flows.

9. Contributions are not investment gains

An account that rises from £10,000 to £18,000 has not earned 80% if the investor added £9,000. Account-value charts can look impressive simply because capital was added.

Track three items separately:

1. Net contributions — money added minus money withdrawn.
2. Investment profit or loss — ending value minus net contributions and starting capital.
3. Rate of return — calculated with a method that accounts for timing.

This separation prevents deposits from being mistaken for performance.

10. Benchmark comparison

Compare like with like:

• Compare a portfolio's TWR with a benchmark's total return over the same dates.
• Do not compare an investor's MWR directly with a benchmark TWR and blame the manager for the whole difference.
• To assess timing decisions, compare actual MWR with a hypothetical cash-flow schedule invested in the benchmark on the same dates.
• Use net-of-fee portfolio returns when evaluating what the investor kept; use gross returns only when the purpose is clearly stated.

Currency also matters. A sterling investor holding US assets may experience a different return from the dollar benchmark because GBP/USD moved.

11. Common mistakes

Using start and end values without adjusting for cash flows

This confuses deposits with returns and withdrawals with losses.

Comparing TWR and MWR as if one must be wrong

Both can be correct. The difference reveals cash-flow timing and capital exposure.

Omitting the ending portfolio value from IRR

Treat the ending value as a positive terminal cash flow when the investment remains open.

Using IRR for irregular dates

Use a dated calculation such as XIRR when timing is uneven.

Ignoring fees and taxes

Gross manager performance and the investor's net result can differ materially. State what is included.

Annualising a very short period

An annualised figure from a few weeks can look extreme and may not represent a repeatable rate.

12. Practical checklist

• Define whether the question concerns manager skill or investor experience.
• Record every deposit and withdrawal with its exact date.
• Value the portfolio at material cash-flow boundaries for TWR.
• Geometrically link sub-period returns; do not add them.
• Use IRR for evenly spaced cash flows and XIRR for actual irregular dates.
• Include the ending value as a terminal cash flow in MWR.
• Check spreadsheet signs and inspect whether multiple IRRs are possible.
• Compare TWR with a time-matched benchmark total return.
• Report gross or net status, currency and annualisation method.
• Review TWR and MWR together when cash-flow timing is part of the decision process.

The core lesson

TWR measures the portfolio engine. MWR measures the journey of the money placed into that engine. When the investor controls deposits and withdrawals, the gap between them is useful information about timing—not a calculation error.

Use TWR to compare strategies. Use MWR to understand the investor's realised experience.

Educational risk disclosure

This tutorial was prepared with AI-assisted research and writing under The Money Man editorial workflow. All amounts and returns are hypothetical and simplified; they exclude fees, taxes and intra-period valuation effects unless stated. This is educational information, not personalised investment advice, an audited performance presentation or a claim of GIPS compliance. Historical and calculated returns do not guarantee future results.