Here's another explanation from the DX.Exchange website:
"MPS MarketPlace Securities, Ltd, under the supervision of the Cyprus Regulator, CySEC, purchases real world stocks, in accordance to token demand in the DX.EXCHANGE platform. They generate smart contracts, ERC20 tokens created on Ethereum’s network to represent those stocks.
The tokens offered for sale are be based on leading public company shares listed on the biggest exchanges like NASDAQ, NYSE, Hong Kong Exchange and Tokyo Stock Exchange. Each Dx.exchange customer, interested in Digital Stocks, is asked to go over an additional small approval form with Term & Conditions, MIFID 2 compliant, where he will need to approve to enter into an agreement with MPS for buy/sell of Digital Stocks. MPS MarketPlace Securities, Ltd is the trust holder of the stocks on behalf of the token holders. Since Digital Stocks are not like CFDs with leverage, there are no carrying costs for the token holders. Each token is backed 1:1 by one share of real stock. These shares are held in a segregated account."
