But the assets that are being securitized come with an obligation from the borrower to pay money back, and they offer a stream of income for a fixed period. Art, cars and other luxury items do not offer those guarantees. The actual objects stay in galleries, showrooms or, with most of the cars that Rally has, at two locations where a caretaker maintains them.

A similar model is used in real estate, in which the use of a property like a condo or a house is divided into fixed amounts and sold to investors, which I wrote about recently. The risk with fractional ownership is that owners struggle to sell their shares.

There is an opportunity for a return. The sponsors of these deals seek to eventually sell the assets to private collectors. Rally sold a Ferrari F430, which was on the platform for six months, to a private collector, earning a 17 percent profit.

But like many investments, proponents put this into the category of future of finance, which is a squishy term at best.

Scott Lynn , founder and chief executive at Masterworks, which is offering shares in a Marilyn Monroe painting by Andy Warhol, points to Lending Club, a pioneer in this investment model. Along with other peer-to-peer groups, Lending Club makes high-interest, short-term loans to individuals with money from other retail investors.

Others paint the securitization of these assets as an equity investment. “Each vehicle is its own entity, whether we issue 2,000 or 5,000 shares,” said Chris Bruno , chief executive of Rally Rd. “The barrier to entry is one share, from $8 to $200. Each car is independent of the other.”

The potential for appreciation of these private assets and their lack of correlation with the stock market has attracted some investors, while the tangible nature of art and cars versus stocks and bonds has brought in others.