Real Estate Investment Trusts
研究1980-2002年美国房地产投资信托基金（REITs）能否改善投资者按公司规模和账面市值比分类的基准投资组合，发现1986年后权益型REITs能提升均值-方差前沿，而抵押型REITs无分散化收益。
Can investors improve their investment opportunity sets by adding a real estate investment trust (REIT) portfolio to benchmark portfolios sorted by firm size and book-to-market ratio? According to U.S. REIT performance data over 1980–2002, REITs after 1986 improve the mean-variance frontier set. Equity REITs appear to be non-redundant financial assets, which helps to enhance the completeness of the financial market. Mortgage REITs provide no diversification benefits in the sample period.