No withdrawals are required if you are the original owner. Overall, the best investments for Roth IRAs are those that generate highly taxable income, be it dividends or interest, or short-term capital gains. Money market funds , CDs, and other low-risk, cash-equivalents investments are also ill-suited for a Roth, but for a different reason. Table of Contents Expand. REITs invest in most kinds of real estate, including:. Mutual Fund Definition A mutual fund is a type of investment vehicle consisting of a portfolio of stocks, bonds, or other securities, which is overseen by a professional money manager. Take a look at a side-by-side comparison:.