When you think about objects that you can invest in for hopefully high returns, you tend to think of things like gold, jewelry, art, antiques, and so on. A new study from the economists at the Higher School of Economics in Russia recently released a study that presents a new and unique lucrative alternative: Lego sets.

Throughout the course of their study, the economists discovered that the market prices of the retired Lego sets sold on the secondary market grow by at least 11% annually, which is higher than average returns provided by gold, stocks, bonds, and other alternative investments.

Authors of the study analyzed the prices of 2,322 unopened Lego sets from 1987 to 2015 and information about primary sales and online auction transactions. The market for collective toys has become huge lately as people linger on nostalgia and fond memories of toys from their childhoods.

The researchers offer some explanations as to why people pay big bucks for Legos, specifically. The small number of sets proeduced and the limited number of people who want to sell their cherished sets are huge contributing factors to the ROI. Additionally, LEGO has been making Legos since the 1960s and has amassed a legion of nostalgic adult fans who love the older sets.

Before you go running down to your basement to dig out all of your old Legos in hopes of making some extra cash, there are a few things that you need to know. Firstly, the prices for Lego sets on the secondary market vary greatly and range in returns from between -50% to +600% on an annual basis, typically starting to increase about two or three years after a set has been retired.

Prices of small or big sets will increase faster than medium-sized sets, researchers have found. The sets with the biggest growth in value are usually related to famous buildings, movies, or holidays. Special attention is given to Lego sets that were limited edition or given out at promotional events.

Finally, the secondary Lego market isn't something you can jump into easily if you aren't already a Lego fan. There are a lot of sets out there, and it takes a true fan to analyze the market and make a bet on a set that might be worth a lot more someday.

Do you have any sets collecting dust in your basement? Are you still a Lego fan? Share some pics with me of your latest builds!