What's The Best Investment Piece?

You may tell yourself that your new Chanel bag or Dolce & Gabbana dress is an investment, but is it really? Designer resale sites - from eBay to Vestiaire Collective - are blooming as consumers sell off their unwanted purchases (and often buy up new ones), but just because something is expensive doesn't mean it's an investment - as one resale site has found.

The Real Deal - which is on track to do $100 million in sales this year,The Fashion Law reports - has evaluated the 500,000 designer items from 500 brands on its database to find what holds its value, and what depreciates faster than a supercar. And some of the results may surprise you.

Most of the brands that hold their value probably won't come as a shock - Chanel, Louis Vuitton, Hermès, Christian Louboutin, Cartier, Alaïa and Van Cleef & Arpels among them - but those that lose value are more unexpected. Tod's, Versace and Etro are among those that lose their value fastest, while Marni, Alexander Wang, 3.1 Phillip Lim, Marc Jacobs are among the labels that retail for furthest from their original retail price. Although they are relatively young labels, Victoria Beckham, Charlotte Olympia and Alexander McQueen all resale for very close to the original value. Whether they will have Chanel or Hermès's longevity when their pieces become vintage, however, remains to be seen.

Chanel: Always An Investment?

Aside from buzz about a new designer (Phoebe Philo having rejuvenated the resale value of Celine, for example), the most important factor in a piece holding its value is availability.

"Brands have to be careful where they allow their product to be sold," Milton Pedraza, CEO of Luxury Institute, a luxury industry research group, told Fortune - adding that brands that hold their value generally do not discount or sell widely online. "In that sense, it creates a perception of purity, [which the brand will then] back up with design quality and heritage. If I buy something, I will think, 'Wow it has long term investment value.'"

One little footnote though before you go forth and shop: no piece is actually an "investment" unless you plan to ever sell it. Just saying.