Browse earnings, overtime and pay adjustment codes.
SI can identify pay outside ordinary wages, such as a bonus or other additional compensation. The IRS uses the term supplemental wages, but does not require employers to print SI. Withholding on extra pay can differ from the regular paycheck calculation.
How to read this entry
Use the meaning Supplemental income or supplemental wages alongside the column heading. An earnings amount, an employee deduction and an employer-cost memo can have different effects even when their labels look similar.
Example on a pay statement
A $500 extra payment increases gross wages by $500 even if the amount reaching your bank is smaller after withholding. A different withholding percentage is not necessarily a different final tax rate.
Examples illustrate the checking method. They are not a personal tax calculation or a promise of a particular benefit.
What to check with payroll
Ask what the payment covers and whether it was combined with regular wages or processed separately.
Compare related entries
Read the earnings, overtime and pay adjustment codes guide to compare the entries in this part of your statement. Use the full pay stub code directory when a second abbreviation is unfamiliar.
Reference and scope
Official guidance on earnings, overtime and pay adjustment codes provides background on the underlying rules. The actual plan, tax year, jurisdiction and payroll record determine how the rules apply.