Alternative investments refer to asset classes that fall outside the traditional categories of stocks, bonds, and cash. These can include assets like real estate, private equity, hedge funds, commodities, and collectibles. Investors often turn to alternative investments to diversify their portfolios, as they may have different risk and return profiles compared to traditional investments. One key characteristic of alternative investments is that they often require a higher level of expertise and may involve less liquidity, meaning they can be harder to buy or sell quickly. Additionally, they may be less regulated than traditional investments, which can lead to higher potential returns but also increased risks.