Investment in private markets, formerly known as alternative investment, is increasing in Korea and elsewhere. The value of the assets managed by the National Pension Service (NPS) will reach USD 500 billion by the end of 2015 and is forecast to grow to USD 2.5 trillion over the next 30 years. The NPS is currently allocating around 10% of total assets to private markets, and will increase this to 14% within the next 5 years according to its mid-term asset allocation plan. As the Korean economy matures, financial assets held by institutional investors will grow exponentially, from USD 2 trillion in 2014 to USD 5 trillion over the next 30 years. As the local economy becomes saturated, huge growth in financial assets will flow to overseas markets, especially to private markets, which is the theme of this study. Global pension and endowment schemes are also increasing their investments in private markets as returns on fixed incomes have become very low following the financial crisis and the risk-return profile of equity is not attractive. Private markets provide diversification benefits and better returns for investors. Nevertheless, studies on private markets are limited in Korea. Previous international studies have focused on private equity dedicated to buyout and venture or on private equity real estate (PERE) funds. This comprehensive study included both private equity funds and various real asset funds such as real estate. Using Preqin's database, a comprehensive global sample of the IRRs of 2,280 private equity funds and 380 PERE funds from 1985 to 2004 was analyzed. The IRR and standard deviation of various types of private equity fund that have not previously been studied (including not only buyout and venture but also growth, mezzanine, distressed and fund of funds) were analyzed. Various real assets such as real estate, infrastructure, resource and timber were also analyzed. Various types of real estate fund, such as debt, core, value-added, opportunistic and fund of funds, were included in the analysis. This is the first study to analyze the risk-return profiles of various assets, types of private equity and real estate funds. The Sharpe ratio concept of dividing IRR by standard deviation was used to determine the relative attractiveness of different assets in different regions. At the asset level, infrastructure was the most attractive, followed by real estate and private equity. However, type-level analysis gave a different result, and indicated that choice among different types of equity, assets and regions, is an important factor in explaining the risks and returns of private funds. Investors can use the risk-return profiles and information about relative attractiveness provided by this study to make decisions about asset allocation among different asset types in private markets in different regions. Humphery-Jenner studied how the diversification level of buyout and venture funds affected the performance of funds and concluded that diversification positively influenced the performance of funds due to knowledge sharing between different funds. There have been disagreements about whether diversification in industry or region has a positive or a negative effect on the performance of funds. This study extended Humphery-Jenner's previous study to various types of private equity fund and real estate fund. Although Humphery-Jenner used Preqin's industry classification, this study used the Global Industry Classification Standard (GICS) to improve objectivity. For geographic diversification, this study measured the number of continents rather than the number of countries, as used by Humphery-Jenner. For real estate, the number of property types, such as office, retail and residential, was measured. The same method was used to measure geographic diversification. The overall analysis of private equity funds agreed with Humphery-Jenner's findings, confirming that industry and geographic diversification positively influenced fund performance. The number of industries and regions divided by the number of relevant staff negatively influenced fund performance, suggesting that staff numbers should increase as diversification increases. However, the results varied for each type of fund, and firms at different stages were affected differently by diversification. Early-stage venture funds showed benefits from industry diversification. However, the performance of growth funds was negatively associated with diversification, implying that growth funds benefit from concentration rather than diversification. Buyout and mezzanine funds investing in mature-stage firms were positively influenced by geographic diversification. Depending on the stage of the firm, fund managers may thus require either diversification or concentration in region and industry. In real estate, diversification had no effect on the performance of funds in both the overall market and at the individual type level. In conclusion, some types of private equity fund receive benefits from industrial or geographic diversification due to knowledge sharing. Growth funds benefit from concentration by focusing on the strengths of managers. Managers of other private equity funds and real estate funds may choose either diversification or concentration strategies.