The required rate of return (RRR) is the minimum return investors expect to earn from investing in a company, reflecting the level of risk associated with the investment. Higher-risk projects typically demand higher returns, making RRR a critical concept in corporate finance and equity valuation. It helps investors determine whether to buy a security or invest in a project by setting a benchmark for acceptable returns.

The RRR serves as a threshold, distinguishing feasible investments from those not. If an investment's return is below the RRR, it is generally considered unfavorable. The RRR also accounts for risk, with riskier projects requiring higher returns to compensate for the increased uncertainty.

On the other hand, the cost of capital represents the expense a company incurs to finance its operations and growth, whether through debt or equity. This cost is what the company must pay to obtain funds from lenders and shareholders.

RRR and the cost of capital are crucial for making sound investment decisions. Investors and companies use these metrics to ensure that returns exceed the risks and costs, leading to profitable and well-informed financial choices.