In financial contexts, deferral means a delay in the standard tax treatment that normally occurs when you receive income or undertake a specific transaction, such as a stock sale.
Example: For large concentrated stock holdings, financial advisors have developed techniques to diversify risk and monetize the position without technically selling the shares and paying capital-gains tax at that time. All these methods involve complex interpretations of the Internal Revenue Code and securities regulations and need to follow closely the limits of the constructive-sale rules.