Related literature and previous research -- Optimal level of diversification in private equity funds -- Construction of data set and variables -- Choice of portfolio strategies by private equity firms -- Performance of private equity funds: does diversification matter? -- Summary.

Driven by the convergence of international financial public markets, investors around the globe are searching for alternative asset classes which enable diversification of their portfolios while earning attractive returns. Private equity, denominating equity investments in privately held companies, promises to meet both criteria. As a result, over the last three decades, private equity has become an important ingredient in the portfolios of institutional investors, such as banks, insurance companies, and pension funds. Ulrich Lossen explores the choice of portfolio strategies by private equity firms and the impact of this choice on funds' performance. Therefore, he applies advanced econometric methods to a unique data set of private equity funds. In a first step, he analyzes the influence of external factors on the choice of private equity firms to diversify their portfolios across different dimensions, such as financing stages, industries, and geographic regions. Then, he examines the impact of such diversification on private equity funds' performance. The findings can help investors and private equity managers in making proper investment decisions.