Your client has very limited investment knowledge and is confused about what is meant by...

The marginal tax rate is the percentage of tax that an individual pays on the last dollar of income earned in a given year. It is also the tax rate that applies to any additional income earned in that year. The marginal tax rate varies depending on the individual’s income level and tax bracket. For example, if an individual’s taxable income for the year is $50,000 and the tax rate for that income bracket is 20%, then the marginal tax rate is 20%. This means that the individual pays 20% tax on the last dollar of income earned, as well as on any additional income earned above $50,000.

References = Canadian Investment Funds Course, Unit 5: Types of Investments, Lesson 6: Taxation, Section 5.6.1: Income Tax 1; CIFC prepkit, Chapter 5: Types of Investments, Question 5.6.1 2