An alternative investment, also known as an alternative asset or alternative investment fund (AIF), is an investment in any asset class excluding stocks, bonds, and cash. The term is a relatively loose one and includes tangible assets such as precious metals, collectibles (art, wine, antiques, vintage cars, coins, musical instruments, or stamps) and some financial assets such as real estate, commodities, private equity, distressed securities, hedge funds, exchange funds, carbon credits, venture capital, film production, financial derivatives, cryptocurrencies, non-fungible tokens, and Tax Receivable Agreements. Investments in real estate, forestry and shipping are also often termed "alternative" despite the ancient use of such real assets to enhance and preserve wealth. Alternative investments are to be contrasted with traditional investments. As the definition of alternative investments is broad, data and research vary widely across the investment classes. For example, art and wine investments may lack high-quality data. The Goizueta Business School at Emory University has established the Emory Center for Alternative Investments to provide research and a forum for discussion regarding private equity, hedge fund, and venture capital investments. In recent years, the growth of alternative finance has opened up new avenues to investing in alternatives. These include the following: In a 1986 paper, William Baumol used the repeat sale method and compared prices of 500 paintings sold over 410 years before concluding that the average real annual return on art was 0.55%. Another study of high-quality oil paintings sold in Sweden between 1985 and 2016 determined the average return to be 0.6% annually. However, art gallerists are sometimes ambivalent to the idea of treating artwork as an investment. Art is also notoriously difficult to value, and there are quite a few factors to bear in mind for art valuation. Equity crowdfunding platforms allow "the crowd" to review early-stage investment opportunities presented by entrepreneurs and take an equity stake in the business.