Financial economics

Financial economics is a branch of economics that studies how financial markets, financial institutions, assets, and economic decisions interact. It applies economic theory and quantitative methods to questions involving the allocation of capital, valuation of financial assets, risk, investment, interest rates, and financial decision-making.

Financial economics is closely related to finance, financial econometrics, monetary economics, and macroeconomics.

Scope

Financial economics examines how individuals, firms, investors, governments, and financial institutions make decisions under conditions of uncertainty.

Major areas include:

Time value of money

A fundamental concept in financial economics is the Time value of money, which states that money available today can have a different economic value from the same nominal amount received in the future.

The present value of a future cash flow can be expressed as:

$P V = \frac{C F_{t}}{(1 + r)^{t}}$

where:

$P V$ = present value;
$C F_{t}$ = cash flow received at time $t$ ;
$r$ = discount rate;
$t$ = time period.

Risk and return

Financial economics studies the relationship between investment risk and expected return.

A simplified risk-premium relationship is:

$Risk Premium = E (R_{i}) - R_{f}$

where:

$E (R_{i})$ = expected return of asset $i$ ;
$R_{f}$ = risk-free rate.

Investors may require additional expected return as compensation for bearing financial risk.

Portfolio theory

Modern portfolio theory studies how investors can combine assets into portfolios to achieve desired combinations of expected return and risk.

For a portfolio containing $n$ assets, expected portfolio return is:

$E (R_{p}) = \sum_{i = 1}^{n} w_{i} E (R_{i})$

where:

$E (R_{p})$ = expected portfolio return;
$w_{i}$ = portfolio weight of asset $i$ ;
$E (R_{i})$ = expected return of asset $i$ .

Portfolio risk depends not only on the individual risks of the assets but also on their relationships with one another.

Capital Asset Pricing Model

The Capital asset pricing model (CAPM) describes the relationship between expected return and systematic risk.

The CAPM equation is:

$E (R_{i}) = R_{f} + β_{i} [E (R_{m}) - R_{f}]$

where:

$E (R_{i})$ = expected return of asset $i$ ;
$R_{f}$ = risk-free rate;
$β_{i}$ = beta of asset $i$ ;
$E (R_{m})$ = expected market return.

CAPM distinguishes systematic market risk from diversifiable asset-specific risk.

Asset pricing

Asset pricing is a central area of financial economics concerned with determining the theoretical or expected value of financial assets.

Models may relate asset prices or expected returns to factors such as:

interest rates;
expected cash flows;
market risk;
consumption;
macroeconomic conditions;
investor preferences;
liquidity;
uncertainty.

The general present-value relationship can be expressed as:

$P_{0} = \sum_{t = 1}^{n} \frac{E (C F_{t})}{(1 + r_{t})^{t}}$

where $E (C F_{t})$ represents the expected cash flow at time $t$ and $r_{t}$ represents the relevant discount rate.

Efficient market hypothesis

The Efficient-market hypothesis (EMH) proposes that financial asset prices reflect available information to varying degrees depending on the form of market efficiency considered.

Commonly discussed forms include:

weak-form efficiency;
semi-strong-form efficiency;
strong-form efficiency.

The hypothesis has important implications for investment management and the possibility of systematically earning abnormal returns.

Financial markets

Financial economics studies the operation and economic functions of financial markets, including:

Financial markets facilitate the transfer of capital between participants and enable the trading and pricing of financial claims.

Corporate finance

Corporate finance applies financial-economic principles to decisions made by firms.

Major areas include:

A firm's financing decision can be represented conceptually as:

$Capital Structure = Debt + Equity$

The relative use of debt and equity affects financing costs, financial risk, and potentially the value of the firm.

Financial intermediation

Financial economics examines the role of financial intermediaries in transferring funds between savers and borrowers.

Examples include:

Financial intermediaries can reduce transaction costs, facilitate risk sharing, provide liquidity, and address information asymmetries.

Interest rates

Interest rates play a central role in financial economics because they affect borrowing costs, investment decisions, asset prices, and the valuation of future cash flows.

The relationship between a future cash flow and its present value can be expressed as:

$P V = \frac{F V}{(1 + r)^{n}}$

where:

$F V$ = future value;
$r$ = interest or discount rate;
$n$ = number of periods.

Holding other variables constant, an increase in the discount rate reduces the present value of a future cash flow.

Risk-adjusted performance

Financial economics provides several measures for evaluating investment returns relative to risk.

The Sharpe ratio is:

$Sharpe Ratio = \frac{R_{p} - R_{f}}{σ (R_{p})}$

The Treynor ratio is:

$Treynor Ratio = \frac{R_{p} - R_{f}}{β_{p}}$

The Information ratio is:

$Information Ratio = \frac{R_{p} - R_{b}}{σ (R_{p} - R_{b})}$

These measures use different definitions of risk and therefore provide different perspectives on investment performance.

Behavioral finance

Behavioral finance examines how psychological factors and behavioral biases can influence financial decisions and market outcomes.

It challenges the assumption that investors always behave according to fully rational economic models.

Examples of behavioral factors include:

overconfidence;
loss aversion;
anchoring;
herd behavior;
confirmation bias.

Information asymmetry

Financial economics also examines situations in which different market participants possess different information.

Information asymmetry can contribute to problems such as:

These problems can affect lending, insurance, investment, corporate governance, and financial-market efficiency.

Uncertainty and risk

Financial economics distinguishes between different forms of uncertainty and risk.

Systematic risk is associated with broad economic or market factors and cannot generally be eliminated through diversification.

Unsystematic risk is specific to an individual company, security, or project and can potentially be reduced through diversification.

A simplified representation is:

$Total Risk = Systematic Risk + Unsystematic Risk$

Applications

Financial economics is applied in areas including:

investment analysis;
portfolio construction;
financial valuation;
corporate investment decisions;
capital budgeting;
banking;
insurance;
pension management;
financial regulation;
risk management;
monetary policy analysis;
international capital markets.

Relationship with finance

Financial economics provides theoretical and analytical foundations for many areas of finance.

Finance generally focuses on practical financial decision-making and management, while financial economics emphasizes the economic theories and models underlying financial markets and decisions.

The distinction is not absolute, and the two fields overlap extensively.

Importance

Financial economics provides a framework for understanding how financial assets are valued, how risk and return are related, how capital is allocated, and how financial markets and institutions operate. Its theories and models form the foundation for many practices in investment management, corporate finance, banking, financial valuation, and risk management.

Financial economics

Contents

Scope

Time value of money

Risk and return

Portfolio theory

Capital Asset Pricing Model

Asset pricing

Efficient market hypothesis

Financial markets

Corporate finance

Financial intermediation

Interest rates

Risk-adjusted performance

Behavioral finance

Information asymmetry

Uncertainty and risk

Applications

Relationship with finance

Importance

See also