Many women joke and say that a Birkin bag is an "investment purchase." But a new study suggests that purchasing the famously expensive handbag could actually be a smart move.

Racked has cited a study from Baghunter that states that over the past 35 years, Hermes Birkin bags have increased in value over 500%. Baghunter says that the handbag increases in value on average 14.2% every year.

Baghunter says that Birkin bags have never decreased in value over the years — whereas gold and the S&P 500 have. The study flatout says it's a "historically safer investment than a stock market."

Here's a graphic showing some of the study's finds, courtesy of Baghunter:

But it's not so easy to purchase one of these bags.

To start, you can't purchase a bag on Hermes's website — they're only available in stores. (You can, however, get bags through third party websites, or through luxury reselling websites, like TheRealReal.)

They're notoriously expensive, typically starting out at around $10,000. This summer, a bag sold for a record-setting $221,846 at a Christie's auction in Hong Kong.

The Hermes Birkin bag, one of the bags affected by the smelly problem, can retail for up to $20,000. Michael Buckner/Getty Images

They are status symbols, so the average person often cannot obtain one.

In fact, the company allegedly makes it intentionally difficult for people to get the bags.

Hermes "made a point to communicate that there is a limited supply of these gold nuggets," Constance Dunn, marketing and branding extension instructor at University of California, Santa Barbara, said to Fortune this past summer.

The company famously has a wait list for bags, as well, which Dunn described to Fortune as a "particularly clever tactic that causes even greater salivation among the image-obsessed and grasping. We are the descendants of those who successfully recognized resources in scarce supply, and made a point to acquire and utilize them."

But at least they're an investment.