Time-Weighted vs Money-Weighted Return: Which One Wins?

If you have ever compared your portfolio return to a benchmark and felt confused by the gap, there is a good chance the two numbers are not measuring the same thing. The debate around time-weighted vs money-weighted return sits at the heart of that confusion — and sorting it out takes about ten minutes of honest thinking.

Both metrics are legitimate. Both answer a real question. But they answer different questions, and mixing them up leads to conclusions that are quietly misleading.

What Each Metric Actually Measures

Time-Weighted Return (TWR)

Time-weighted return isolates the performance of the investments themselves by stripping out the effect of cash flows — the deposits and withdrawals you make. Each period between cash flows is calculated separately, then the sub-periods are geometrically linked.

The result: TWR tells you how €1 invested at the very start would have grown, regardless of how much money you actually had in the portfolio at any given moment.

This is why fund managers are evaluated on TWR. A manager cannot control when clients pour money in at peaks or pull it out at troughs. TWR removes that noise.

Money-Weighted Return (MWR)

Money-weighted return — also called the Internal Rate of Return (IRR) — weights each cash flow by how long it was invested. Larger deposits that stayed in longer have more influence on the final number.

In plain terms: MWR tells you the actual annualised return you achieved on your money, given your specific deposit and withdrawal timing.

This is the number that matters for your personal financial outcome.

A Concrete Example with Numbers

Imagine you invest in a fund over two years.

TWR calculation:

MWR (IRR) calculation:

Your cash flows: −€10,000 at t=0, −€40,000 at t=1, +€47,450 at t=2. Solving for the rate that sets the net present value of those flows to zero gives approximately −2.4% per year.

Same portfolio. Same market movements. TWR: +17%. MWR: −2.4%.

The reason: you deposited a large sum (€40,000) right before a −10% year. The TWR correctly credits the manager for a net positive strategy over two years. The MWR correctly tells you that your money lost ground because of when you added it.

Neither number is wrong. They are answering different questions.

When to Use Each One

Use TWR when:

• Comparing your portfolio against a benchmark index or another fund
• Evaluating whether your asset allocation strategy is working, independent of your saving behaviour
• Assessing a fund manager's skill (this is the industry standard for a reason)

Use MWR (IRR) when:

• Measuring your actual personal financial outcome
• Deciding whether to continue with a strategy given your real cash flows
• Calculating the true return on a single asset — a rental property, a private equity stake, or a position you built up over time with multiple purchases

For self-directed investors, MWR is almost always the more personally relevant number. TWR is the right tool for benchmarking. You probably need both.

This distinction also matters when you track your entire net worth across multiple asset classes — a property bought in stages, a pension topped up monthly, and a stock portfolio all behave very differently under each metric.

The Compounding Angle: CAGR and How It Fits In

You may also encounter CAGR — Compound Annual Growth Rate. CAGR is a simplified version of TWR applied to a single start and end value, assuming no intermediate cash flows. It is useful for clean, single-investment scenarios.

When cash flows exist, CAGR becomes imprecise. MWR (IRR) handles irregular cash flows correctly; CAGR does not. If you want to understand the relationship between these metrics in more depth, the post on CAGR and annualised growth covers the mechanics.

What to Watch Out For

A few specific pitfalls:

• Short time horizons: Both metrics become noisy over periods under one year. An annualised IRR on a three-month position can look dramatic in either direction.
• Illiquid assets: Real estate and private funds often have estimated valuations mid-period. Your MWR is only as good as the NAV or appraisal you feed into it.
• Multi-currency portfolios: If you hold assets in USD, GBP, and EUR, your return figures will differ depending on whether currency gains and losses are included. Always confirm which currency your tracker uses as the base. Multi-currency portfolio tracking explains the conventions to look for.
• Tax: Neither metric accounts for taxes by default. Your post-tax MWR is what you actually keep. Tax treatment of gains varies significantly by country and changes over time — confirm the rules in your jurisdiction or consult a tax professional before drawing conclusions.

Practical Advice for Self-Directed Investors

You do not have to choose one metric and ignore the other. A sensible approach:

1. Track MWR (IRR) per asset to understand what each position has actually contributed to your wealth.
2. Track TWR at the portfolio level to benchmark against an index — this is a fair comparison because the index has no cash flows.
3. Review the gap between the two. A large positive gap (TWR >> MWR) means you tended to invest more just before underperformance. A negative gap (MWR >> TWR) means your timing added value — or you were lucky.
4. Keep your records clean: accurate entry dates, correct cost basis after corporate actions, and consistent currency treatment. Garbage in, garbage out — no formula fixes bad data. Proper record-keeping for dividends and splits is a prerequisite.

The goal is not to game the metric that looks best. It is to understand what is actually happening with your money.

WealthFlow calculates IRR per asset automatically across your stocks, ETFs, crypto, investment funds (tracked by ISIN and NAV), pension plans, and real estate — giving you the money-weighted picture for every position without manual spreadsheet work. Pro users can also export a FIFO tax-report CSV and use benchmark comparison to set TWR in context. Start with the Free plan and see what your money has genuinely earned.