Money weighted vs time weighted return are two fundamental ways investors evaluate how well a portfolio has performed, yet they answer different questions about the impact of cash flows and market movements. Understanding the distinction helps you choose the right metric for assessing a manager’s skill versus the effect of your own contributions and withdrawals. Below is a detailed, easy‑to‑follow guide that breaks down each concept, shows how they are calculated, and clarifies when each is most useful No workaround needed..
Counterintuitive, but true.
Understanding Investment Performance Metrics
The moment you look at an investment statement, the return figure you see can be derived from several methods. Both express performance as a percentage, but they treat the timing and size of cash flows differently. The two most common are time‑weighted return (TWR) and money‑weighted return (MWR). This difference matters because it determines whether the return reflects the pure investment strategy or the investor’s actual experience.
Short version: it depends. Long version — keep reading.
What is Time‑Weighted Return (TWR)?
Time‑weighted return measures the compound growth rate of a portfolio independent of external cash flows. It breaks the overall period into sub‑periods whenever a contribution or withdrawal occurs, calculates the return for each sub‑period, and then geometrically links them. By doing this, TWR isolates the effect of the investment decisions made by the portfolio manager, making it the industry standard for comparing managers or funds.
What is Money‑Weighted Return (MWR)?
Money‑weighted return, also known as the internal rate of return (IRR), treats the portfolio as a cash‑flow problem. It finds the single discount rate that equates the present value of all cash inflows (contributions, ending market value) with the present value of all cash outflows (withdrawals, beginning market value). Because it weights each period by the amount of money actually invested, MWR reflects the investor’s personal experience, including the impact of timing their own deposits and withdrawals Easy to understand, harder to ignore..
Key Differences Between Money Weighted and Time Weighted Return
Cash Flow Sensitivity
- TWR is insensitive to when you add or remove money. Large contributions right before a market rally do not inflate the return; they are neutralized by the sub‑period linking.
- MWR is highly sensitive to cash flow timing. Investing a large sum just before a market upswing will boost the MWR, while withdrawing before a downturn will penalize it.
Use Cases
| Metric | Best Suited For | Typical Users |
|---|---|---|
| Time‑Weighted Return | Evaluating manager skill, comparing funds, benchmarking against indices | Fund analysts, institutional investors, performance consultants |
| Money‑Weighted Return | Assessing personal portfolio outcome, financial planning, client reporting | Individual investors, wealth advisors, private clients |
How to Calculate Each Return
Steps for Calculating Time‑Weighted Return
- Identify sub‑periods: Split the total evaluation horizon at every point where a cash flow (contribution or withdrawal) occurs.
- Compute sub‑period return: For each sub‑period, calculate
[ R_i = \frac{EV_i - BV_i}{BV_i} ]
where (BV_i) is the beginning market value and (EV_i) is the ending market value of that sub‑period (excluding cash flows). - Link the returns: Multiply the growth factors:
[ (1 + TWR) = \prod_{i=1}^{n} (1 + R_i) ]
Then subtract 1 to express TWR as a percentage. - Annualize (if needed): If the evaluation period is not one year, raise the cumulative factor to the power of ( \frac{12}{\text{months}} ) or ( \frac{1}{\text{years}} ) and subtract 1.
Steps for Calculating Money‑Weighted Return (IRR)
- List all cash flows: Include the beginning market value as a negative outflow, each contribution as a negative outflow, each withdrawal as a positive inflow, and the ending market value as a positive inflow.
- Set up the NPV equation:
[ \sum_{t=0}^{N} \frac{CF_t}{(1 + r)^t} = 0 ]
where (CF_t) is the cash flow at time (t) and (r) is the unknown rate. - Solve for (r): Use trial‑and‑error, a financial calculator, or spreadsheet functions like
XIRRorIRRto find the rate that makes the net present value zero. - Express as a percentage: The resulting (r) is the money‑weighted return for the period.
Practical Example
Imagine an investor starts the year with $100,000. Three months later they add $50,000. Six months after the start (three months after the contribution) the portfolio is worth $180,000. They then withdraw $30,000, and at year‑end the portfolio stands at $170,000 But it adds up..
Time‑Weighted Return
- Sub‑period 1 (0‑3 mo):
Beginning = $100,000, End (before contribution) = $115,000 → (R_1 = 0.15) (15%). - Sub‑period 2 (3‑6 mo):
Beginning = $115,000 + $50,000 = $165,000, End (before withdrawal) = $180,000 → (R_2 = 0.0909) (9.09%). - Sub‑period 3 (6‑12 mo):
Beginning = $180,000 – $30,000 = $150,000, End = $170,000 → (R_3 = 0.1333) (13.33%).
