Sealed LEGO Sets Beat Gold and Stocks in One Study. Here Is What That Study Actually Covered
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7 min read
Imagine a sealed LEGO box that costs Rp5.000.000 today. Ten years later, it sells for Rp14.000.000. That is the headline version of a famous study on LEGO set investment, and it is half true.
Researchers found that sealed, retired LEGO sets returned about 11% a year on average. That beat gold, bonds and large-company stocks over the period they studied. But the study did not cover the last ten years, and it did not cover every set. This post shows what it did cover, so you can judge the claim for yourself.
The study is called "LEGO: The Toy of Smart Investors." Two economists, Victoria Dobrynskaya and Julia Kishilova of the Higher School of Economics in Moscow, wrote it. It was published in the journal Research in International Business and Finance.
Here is what they looked at:
Here is what they reported, according to the HSE University summary and the SSRN paper page:
| Result | Figure |
|---|---|
| Average yearly return | At least 11% |
| Average yearly return after inflation (real return) | About 8% |
| Range of yearly results across sets | About -50% to +600% |
Read the last row twice. The average is 11%. But some sets lost half their value in a year, and some rose six-fold. The average hides a very wide spread.
The study's title promise depends on two words: sealed and retired.
Retired means LEGO stopped making the set. According to Brick Fanatics, a typical set stays in production for roughly 18 months before it retires. After that, no new copies are made. The supply only shrinks, because some boxes get opened and built.
Sealed means the box was never opened. A built set is a used toy. A sealed one is a collectible. The researchers looked at unopened sets for this reason.
This is a simple supply story. If fewer boxes exist and the same number of fans want one, the price goes up. The study also found that prices tend to start rising two or three years after a set retires. Right after retirement, shops and sellers often still hold unsold copies.
A set that is still on shelves does not get this effect. There is nothing scarce about it yet.
The same study found that licensed and display-type sets did better. Examples reported in coverage include Star Wars sets like the Millennium Falcon, and the Taj Mahal set. Sets based on popular films, TV shows and architecture earned higher returns.
Theme matters a lot, and the spread between sets is wide. Some retired sets lost money. Others multiplied.
The study also found the returns were not tied to the usual stock market drivers. The authors say the returns have almost no link to market, value, momentum or volatility risk. They do link strongly to size. In plain words, the returns behave like a small, niche market, not like a mini stock index.
Now the part most social media posts skip.
It is not the last ten years. The data ends in 2015. Nothing in this study tells you about 2016 to 2026.
It is an average of survivors you can name afterwards. It is easy to look back and see which sets rose. Nobody can see that on the day of purchase.
It is a price, not cash in your hand. To get the price, you have to sell. Selling means a marketplace fee, packing and shipping. Unlike a stock, you cannot sell a LEGO box with one tap.
It needs storage. A box that gets crushed, wet or faded loses its collector value. You also hold it for years, so the money sits idle.
Here is a made-up example to show how costs bite. This is NetWort's own arithmetic, not a market figure.
| Item | Amount |
|---|---|
| Buy a sealed set | Rp5.000.000 |
| Value after 10 years at 11% a year | About Rp14.200.000 |
| Assume selling costs eat 15% of the sale (illustration only) | About Rp2.100.000 |
| What you keep | About Rp12.100.000 |
| Yearly return after that cost | About 9.2% |
The fee in this table is an assumption. Real fees depend on the marketplace and the shipping cost. The point is simple: costs take a bite out of a collectible return, and the study's 11% is a price return before that bite.
For a more recent view, BrickEconomy tracks resale and market values across LEGO sets. In its monthly recaps for June, July and August 2026, it reported average yearly appreciation of 6.4% across roughly 18,200 to 18,300 active sets (retrieved 3 October 2026, via search summaries of BrickEconomy's market recaps).
That is a different number from the 11% study. It covers active sets, not only retired ones, and it is a different time period. It does not mean the study was wrong. It means the figure depends on which sets you pick and when.
To put the gap in plain terms, here is what Rp5.000.000 grows to over 10 years at each rate (NetWort's own compounding, before any costs):
| Yearly return | Rp5.000.000 after 10 years |
|---|---|
| 6.4% | About Rp9.300.000 |
| 11% | About Rp14.200.000 |
Compare this with a broad stock index. You can look at an S&P 500 fund like SPY on NetWort over any period you like. Then check how the overall market looks today. Stocks pay you without needing a box in your closet and a buyer later.
If you already own sealed sets, treat them like any other collectible. Value them at what a real buyer would actually pay today, after fees. Do not use the highest listing you can find.
You can add them as a manual asset on NetWort's Holdings page. Pick the Luxury Goods group and the Collectible sub-category. Enter what you paid, then update the value once or twice a year using real sold prices, not asking prices. That way your net worth shows a number you could actually collect.
The research is real. Sealed, retired LEGO sets did beat several traditional assets between 1987 and 2015, with a huge spread between winners and losers. But the claim does not cover the last decade, it ignores selling and storage costs, and it does not make any one set a safe bet.
Before you count a LEGO collection as part of your wealth, check what similar sets actually sold for, and subtract what it costs to sell. Then record the result on the Holdings page, so the number you track is the one you could really get.