Net Worth vs. Portfolio Performance

Your account balance is up 30% this year. You feel like a good trader. Then you remember you deposited fresh cash almost every month. So how much of that 30% came from your decisions, and how much came from your paycheck?

That question matters more than most traders admit. A growing balance and a good strategy look identical on a screen. They are not the same thing. If you keep funding a losing account, the balance can climb while your actual investing performance quietly bleeds. You end up feeling skilled when the market and your own deposits are doing the work.

Net worth vs. portfolio performance is the distinction that settles it. This post separates the two numbers traders confuse all the time: the growth of your net worth (or account balance) and your actual portfolio performance, meaning how the invested money itself did.

TL;DR

• Account balance change mixes two things: money you added and money your investing earned.
• A rising balance can hide a losing strategy whenever you keep depositing cash.
• Time-weighted return (TWR) isolates strategy performance by removing the effect of deposits and withdrawals.
• Money-weighted return (MWR/IRR) measures your personal result, including the timing of your cash flows.
• You need both: TWR to judge the strategy, MWR to judge your real outcome.

Net worth and portfolio performance are two different numbers

Start with a definition, because the whole confusion lives here.

Your net worth, or in trading terms your account balance, goes up for two reasons. Either you put money in, or your positions gained value. When you look at a balance that went from $10,000 to $13,000, you cannot tell which reason applies. The screen shows $13,000 either way.

Investing performance is narrower. It asks one thing: for every dollar that was actually invested, how much did it grow or shrink? Deposits are not performance. Moving $2,000 from your bank into your brokerage does not make you a better trader. It just relocates money you already had.

Here is the trap in one line. If you judge yourself by the balance, every deposit flatters your scorecard.

Consider a simple case. You start the year with $10,000. Your positions lose 10%, so by pure investing performance you are down to $9,000. But across the year you deposited $5,000 in fresh cash. Your ending balance is roughly $14,000. The account is up 40% on paper. Your strategy lost money. Both statements are true at the same time.

The balance rose. The investing lost money. Deposits (blue) did the lifting. Strategy performance (red) was negative. Judging yourself by the green bar hides the red one.

If you have ever wondered why your account "feels" like it is doing better than your win rate suggests, this gap is usually the reason. It is one of the quiet leaks in your portfolio performance: a scorecard that rewards deposits instead of decisions.

Why the account balance can hide a losing strategy

The reason a rising balance is misleading comes down to how a simple return is calculated. A simple return divides your gain by the money you started with. It does not care when the money arrived.

Investment analysts have a specific warning about this. Simple return "is often the most misleading," writes Wealthfront, because "a large, late addition of cash can massively reduce the return of an account or mask losses in that account." The direction of the distortion depends on when your cash lands and what happens next.

Two versions of the same trap:

• Cash masks a loss. You deposit a big chunk near the end of the year. The new cash sits mostly idle, so it did not lose anything. Blended into the balance, it dilutes the loss your older positions took. The account looks flatter and safer than your trading actually was.
• Cash flatters a gain. You feed money in steadily all year. Every deposit lifts the balance. If you only track the balance, each deposit reads like progress, even in a year your positions barely moved.

The core defect is that a balance answers "how much money is here now?" It does not answer "how well did the money that was invested actually perform?" Those are different questions, and only the second one measures skill.

There is a related crossover worth naming. Early in a trader's life, deposits dominate the balance because the account is small relative to your income. As the account grows, returns start to outweigh new contributions. As Physician on FIRE puts it, at some point "your portfolio makes more money than you." Before that point, a rising balance says almost nothing about your investing. It mostly reflects your savings rate.

The fix: measure return in a way that ignores your deposits

To judge the strategy, you need a return number that strips deposits and withdrawals out. There are two standard tools, and they answer two different questions.

Time-weighted return (TWR) measures how the invested money performed, independent of when you added or removed cash. It works by cutting the period into segments at each deposit or withdrawal, calculating the return inside each segment, then chaining those segments together. Because the cash flows fall on the segment boundaries, they never distort the return inside a segment. As CIBC's Investor's Edge describes it, TWR "strips out the impact of their cash flows," so you see how the underlying positions did.

Money-weighted return (MWR), also called the internal rate of return (IRR), does the opposite. It deliberately includes the timing and size of every deposit and withdrawal. It answers "how did I do, given when I actually put money in?" If you added a lot right before a drop, MWR reflects that mistake. TWR would not.

How different can they be? Sharesight walks through a case where an investor buys 1,000 shares at $1.00, buys 1,000 more at $2.00, then sells all 2,000 at $1.25. The investor lost $500 in real money. Yet the time-weighted return was positive at 11.80% per year, while the money-weighted return was negative at -12.77% per year. The strategy (holding the share) technically drifted up over the window. The investor's timing (buying heavily at the high) is what lost the money. One number praises the asset, the other indicts the decision. That gap is exactly what a raw balance can never show you.

This is not a fringe idea. The CFA Institute's Global Investment Performance Standards require professional firms to report a time-weighted rate of return precisely so that client-driven deposits and withdrawals do not distort the picture of how the manager actually performed. The pros solved this problem decades ago. Retail traders staring at a balance are the ones still fooled by it.

Which number should you actually watch?

You want both, for different jobs.

• Use time-weighted return to grade the strategy. This is the honest answer to "am I any good at this?" It is also the only fair way to compare yourself to a benchmark, because an index return has no deposits to distort it. If you want a scoreboard against the market, benchmark your portfolio against the S&P 500 using time-weighted return on both sides. Comparing a deposit-inflated balance to the index is comparing two different things.
• Use money-weighted return to grade your real result. TWR can look great while your account still shrinks, if your timing was bad. MWR catches that. It is the closer answer to "did my money actually grow?"

A practical rhythm: check TWR when you want to know whether your edge is real, and check MWR when you want to know whether the whole effort paid off. When the two diverge sharply, the gap is your cash-flow timing, and that is a skill worth studying on its own.

One more number belongs in the same conversation. A rising balance can also hide how much pain you took to get there. Two accounts can post the same return while one of them nearly halved along the way. That is why it is worth learning to calculate portfolio drawdown alongside your return. Return tells you where you ended. Drawdown tells you how rough the ride was.

How to separate the two in your own tracking

You do not need a finance degree to do this. You need to stop treating deposits as returns. Concretely:

1. Log every deposit and withdrawal with its date. This is the raw material for any honest return. Without dated cash flows, you cannot compute TWR or MWR at all, only the misleading balance change.
2. Compute a time-weighted return across your history to see the strategy's real performance, deposits removed.
3. Compute a money-weighted return to see your personal outcome, timing included.
4. Compare the two. A large gap means your cash-flow timing is doing a lot of the talking, for better or worse.
5. Benchmark the TWR, not the balance, against your index of choice.

A spreadsheet can do all of this with the XIRR function for money-weighted return and a segmented calculation for time-weighted return, though it gets tedious once you have many cash flows. A portfolio tracker that ingests your transactions can compute both automatically. TradeReveal, for example, computes a unified portfolio value and a time-weighted return from your own logged positions and cash, rather than reading a single balance snapshot, so the deposit-driven inflation is stripped out for you. The point is not the tool. The point is that your scoreboard should reward decisions, not deposits.

Frequently Asked Questions

Is net worth a good measure of how well I am investing?

No. Net worth and account balance both mix your contributions with your investment returns. A rising net worth can come entirely from saving more, even if your investing lost money. To judge investing skill specifically, use a return that removes deposits and withdrawals, such as time-weighted return.

Why is my account up but my trades feel like they are losing?

Usually because you have been depositing fresh cash. New deposits raise the balance without being investment gains, so the account climbs even when your positions are flat or down. A time-weighted return will show you the underlying strategy performance with the deposits stripped out.

What is the difference between time-weighted and money-weighted return?

Time-weighted return measures how the invested money performed, ignoring the timing and size of your deposits and withdrawals, which makes it the right tool for judging a strategy and comparing to a benchmark. Money-weighted return (IRR) includes your cash-flow timing, so it measures your actual personal outcome. They can differ substantially when your deposit timing is good or bad.

Which return should I compare to the S&P 500?

Compare your time-weighted return to the index. An index return contains no personal deposits or withdrawals, so it only makes sense to compare it against a return that has also had those cash flows removed. Comparing a deposit-inflated balance change to the index overstates your result.

Do I need special software to calculate this?

No, but it helps. You can compute money-weighted return with the XIRR function in a spreadsheet and time-weighted return by segmenting your history at each cash flow. Both require you to log every dated deposit and withdrawal. Portfolio trackers automate the segmentation once your transactions are recorded.

Final Thoughts

A growing balance is satisfying, and it should be. Building wealth by saving and investing is the whole point. But do not confuse the size of the account with the quality of your investing. Those are two measurements, and only one of them tells you whether your decisions are working.

Separate them once and you will never un-see it. The balance answers "how much is here?" The time-weighted return answers "am I good at this?" The money-weighted return answers "did my money actually grow?" Track all three, and a lucky deposit will never again get mistaken for a skill you do not have.

Sources

• CFA Institute, Overview of the Global Investment Performance Standards (GIPS)
• Wealthfront, What's Your Investment Return? Measuring Portfolio Performance
• Sharesight, Time-weighted vs. money-weighted rates of return
• CIBC Investor's Edge, Comparing Time-Weighted Versus Money-Weighted Rates of Return
• Capitally, Measuring Investment Performance: ROI, CAGR, TWR, MWR and IRR
• Physician on FIRE, When Your Portfolio Makes More Money Than You

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Happy Trading,

The TradeReveal Team