Mutual Fund Theorem

AAA

DEFINITION of 'Mutual Fund Theorem'

An investing theory, postulated by Nobel laureate James Tobin, that states that all investors should hold an identically comprised portfolio of "risky assets" combined with some percentage of risk-free assets or cash. A conservative investor would hold a higher percentage of cash, but would have the same basket of risky investments in his or her portfolio as an aggressive investor.

VIDEO

Loading the player...

BREAKING DOWN 'Mutual Fund Theorem'

The mutual fund theorem came about as a result of the mean-variance framework laid out by Harry Markowitz and his theories on how diversification limits portfolio risk. The viability of the mutual fund theorem has been questioned because several important assumptions must be in place for the theorem to be proved. These include a lack of transaction costs and perfectly transparent markets.

RELATED TERMS
  1. Diversification

    A risk management technique that mixes a wide variety of investments ...
  2. Portfolio

    A grouping of financial assets such as stocks, bonds and cash ...
  3. Modern Portfolio Theory - MPT

    A theory on how risk-averse investors can construct portfolios ...
  4. Asset Allocation

    An investment strategy that aims to balance risk and reward by ...
  5. Capital Asset Pricing Model - CAPM

    A model that describes the relationship between risk and expected ...
  6. Portfolio Management

    The art and science of making decisions about investment mix ...
Related Articles
  1. Investing Basics

    Achieving Optimal Asset Allocation

    Minimizing risk while maximizing return is any investor's prime goal. The right mix of securities is the key to achieving your optimal asset allocation.
  2. Mutual Funds & ETFs

    Major Blunders In Portfolio Construction

    Do you have the best mix of investments? Find out how to make sure.
  3. Active Trading

    Modern Portfolio Theory: Why It's Still Hip

    See why investors today still follow this old set of principles that reduce risk and increase returns through diversification.
  4. Mutual Funds & ETFs

    ETF Analysis: Vanguard Total World Stock

    Learn about the Vanguard Total World Stock exchange-traded fund, which invests in stocks located in numerous countries with a high level of diversification.
  5. Mutual Funds & ETFs

    ETF Analysis: PowerShares S&P 500 Low Volatility

    Find out about the PowerShares S&P 500 Low Volatility ETF, and learn detailed information about this fund that provides exposure to low-volatility stocks.
  6. Mutual Funds & ETFs

    ETF Analysis: iShares US Real Estate

    Learn about the iShares US Real Estate fund, which holds shares of equity and nonequity real estate investment trusts incorporated in the United States.
  7. Mutual Funds & ETFs

    ETF Analysis: iShares S&P Mid-Cap 400 Growth

    Learn about the iShares S&P Mid-Cap 400 Growth exchange-traded fund, which invests in U.S. equities of mid-cap companies that show above-average growth rates.
  8. Mutual Funds & ETFs

    ETF Analysis: SPDR Barclays Short Term Hi Yld Bd

    Find out about the SPDR Barclays Short Term High Yield Bond ETF, and explore detailed analysis of the fund that tracks short-term, high-yield corporate bonds.
  9. Mutual Funds & ETFs

    ETF Analysis: SPDR Barclays Short Term Corp Bd

    Learn about the SPDR Barclays Short-Term Corporate Bond ETF, and explore detailed analysis of the exchange-traded fund tracking U.S. short-term corporate bonds.
  10. Mutual Funds & ETFs

    ETF Analysis: Vanguard Intermediate-Term Bond

    Find out about the Vanguard Intermediate-Term Bond ETF, and delve into detailed analysis of this fund that invests in investment-grade intermediate-term bonds.
RELATED FAQS
  1. What does a high turnover ratio signify for an investment fund?

    If an investment fund has a high turnover ratio, it indicates it replaces most or all of its holdings over a one-year period. ... Read Full Answer >>
  2. What is the utility function and how is it calculated?

    In economics, utility function is an important concept that measures preferences over a set of goods and services. Utility ... Read Full Answer >>
  3. What is the difference between passive and active asset management?

    Asset management utilizes two main investment strategies that can be used to generate returns: active asset management and ... Read Full Answer >>
  4. What percentage of a diversified portfolio should large cap stocks comprise?

    The percentage of a diversified investment portfolio that should consist of large-cap stocks depends on an individual investor's ... Read Full Answer >>
  5. Is there a situation in which wash trading is legal?

    Wash trading, the intentional practice of manipulating a stock's activity level to deceive other investors, is not a legal ... Read Full Answer >>
  6. What types of assets lower portfolio variance?

    Assets that have a negative correlation with each other reduce portfolio variance. Variance is one measure of the volatility ... Read Full Answer >>

You May Also Like

Hot Definitions
  1. Alligator Spread

    An unprofitable spread that occurs as a result of large commissions charged on the transaction, regardless of favorable market ...
  2. Tiger Cub Economies

    The four Southeast Asian economies of Indonesia, Malaysia, the Philippines and Thailand. Tiger cub economy indicates that ...
  3. Gorilla

    A company that dominates an industry without having a complete monopoly. A gorilla firm has large control of the pricing ...
  4. Elephants

    Slang for large institutions that have the funds to make high volumes trades. Due to the large volumes of stock that elephants ...
  5. Widow's Exemption

    In general terms, a widow's exemption refers to the amount that can be deducted from taxable income by a widow, thereby reducing ...
  6. Wedding Warrant

    A warrant that can only be exercised if the host asset, typically a bond or preferred stock, is surrendered. Until the call ...
Trading Center
×

You are using adblocking software

Want access to all of Investopedia? Add us to your “whitelist”
so you'll never miss a feature!