For tax purposes, using the same example above, 2020 is the year of assessment (YA). In other words, YA is the year in which your income is assessed for taxation.
In order to assess the tax, the Inland Revenue Authority of Singapore (IRAS) will look at a company’s income, expenses, etc. for the financial year. This financial year is known as the “base period”.
The Base Period is generally 12 months prior to the assessment year (YA).