Comparisons

BullBenchmark vs your spreadsheet: what a sheet cannot do

Nearly every serious private portfolio starts in a spreadsheet, and many of them can stay there. A sheet is free, it is yours, it does what you tell it, and building one teaches you more about your own money than any dashboard will.

We sell the alternative, so read this page with that in mind. It covers what a spreadsheet does well, the places where it stops being accurate rather than merely slow, and a five-question test you can run on your own file to find out which side of the line you are on.

What the spreadsheet gets right

It costs nothing and it belongs to you. There is no subscription, no account and no company that can change its terms or disappear. Twenty years from now the file will still open.

It fits your situation. Any tracker contains decisions about how a portfolio should be modelled. A sheet contains your decisions, including the odd account, the loan to a friend, the crypto and the property. No product replaces that flexibility.

You can inspect every formula. A formula you wrote is a formula you can check. When a dashboard shows a number you disagree with, you cannot see how it was calculated. When your sheet shows one, you can find out why in about a minute.

Building it teaches you something. Anyone who has worked out a cost basis by hand understands their results better than someone who has only read a percentage off a screen. The arithmetic is worth doing once, which is why how to calculate your portfolio return is written as a method rather than as an advertisement.

Where it stops being accurate

The problems are not about effort. They come from specific pieces of data a sheet does not have, and each one produces numbers that look plausible.

Corporate actions. A share split multiplies your holding and divides the price, a fund merges into another, and a spin-off arrives as shares of something you never bought. Every one of those has to be entered by hand, on the right date, or your share count stops matching your account.

A wrong share count goes unnoticed. What people notice is a return figure that looks slightly off, without knowing why.

Historical exchange rates. If you own anything priced in dollars or pounds, a correct euro cost basis needs the rate of each trade date, and a portfolio chart needs a rate for every day it draws. Most sheets use one rate for everything, which changes years of history by an amount and in a direction you cannot see.

This is the subject of multi-currency portfolio tracking, and it is the most common way a careful spreadsheet is wrong.

Total-return index data. To compare yourself with an index fairly, you need the version of the index that includes reinvested dividends. The number quoted in the news is usually the price version. Comparing yourself with that version gives you an advantage you did not earn, and the gap grows every year.

Time-weighted return. A money-weighted return is easy in a sheet. List your cash flows with dates, add today's value, and the XIRR function gives you the internal rate of return. That is a useful number, but it is not the number you can compare with an index, because it depends on when your money arrived.

A time-weighted return requires cutting your history at every cash flow and valuing all your holdings on each of those days, which means a daily price for every holding you have ever owned. That is a data problem rather than a formula problem, and most sheets stop there.

Both figures, and which question each one answers, are explained in time-weighted vs money-weighted return.

Closed positions and costs. Sold positions tend to disappear from a working sheet, and with them the losses that were the most instructive part of the record. Fees and withheld tax get rounded away as details. What remains is a record of the picks you still hold, and that record flatters you.

Maintenance. The most common failure is that the sheet stops being updated. It is current until a busy quarter, then it is three months behind, then it is a file you no longer open. A history with a gap in it cannot be rebuilt from memory.

The test

Open your sheet and try to answer five questions from it, without new work.

What is your time-weighted return over the last three years?
What would your deposits, on the dates you made them, have become in a total-return index tracker over the same period?
What is your cost basis for a foreign holding, converted at the rate of each purchase date?
What did you realize, in total, on everything you have ever sold, fees included?
What did your holdings pay you in dividends last year, net of tax withheld?

A sheet that answers all five does the job, and you can keep it and skip the rest of this page. A sheet that answers three is normal, and it is probably slightly wrong about the other two.

If you cannot answer the second question at all, that is the gap this product exists to fill. The comparison is a simulated index portfolio that received your deposits on the same dates, rather than a chart overlay, as described in how to check whether your portfolio is beating the S&P 500.

How much time the sheet takes

We cannot tell you how many hours a year a spreadsheet costs you, because we do not know your sheet. You can work it out with three questions.

How long ago was the last update? How many minutes does a month of transactions take, times twelve, times the number of years you intend to keep investing? What happens to the file if you switch brokers, add a second one, or start buying in a third currency?

For some people the answer is small and the sheet wins. For people running two or three brokers, the maintenance grows faster than the portfolio, which is the point made in how to track multiple brokers in one dashboard. Dividend tracking has its own breaking point, covered in dividend tracking in a spreadsheet or a tool.

What the subscription buys

The subscription buys data you cannot easily get and maintenance you would otherwise do yourself, rather than features you could not build. That means daily prices for everything you have ever held, historical exchange rates, total-return index levels, corporate actions applied on the right dates, and broker formats that keep changing.

It also buys the part a sheet cannot practically do at all, which is valuing all your holdings on every day the portfolio existed so that a time-weighted return can be calculated.

BullBenchmark costs €5.99 a month or €59.99 a year, and the first two weeks are free without a card. Your data can be exported in one click, because a tracker you cannot leave is a worse deal than a spreadsheet, whatever else it does.

Keep the sheet

Even people who subscribe tend to keep a sheet for the things a product does not model, such as the pension, the property and the plan. The part to hand over is the part that needs daily prices, historical exchange rates and index data, because that is where a well-built file goes wrong without showing it.

If you want to see the difference on numbers rather than in an argument, the live demo is a sample portfolio across two brokers, with the benchmark calculated the way this page describes.

BullBenchmark reads the transaction export from your broker and shows your return next to the S&P 500 and the Nasdaq 100, fed with the same deposits on the same dates, in your own currency. The first two weeks are free and no card is needed.