Income for MLS purposes takes your taxable income and adds back items like reportable fringe benefits

 The Medicare Levy Surcharge (MLS) is decided using a special definition called income for MLS purposes, which is neither your pure taxable income nor your assessable income in isolation. [1, 2]

According to the Australian Taxation Office, your income for MLS purposes starts with your taxable income and adds back several specific adjustments: [1, 2]

• Taxable income (assessable income minus allowable deductions) [1, 2]
• Reportable fringe benefits [1, 2]
• Net investment losses (including rental property losses) [1]
• Reportable superannuation contributions [1]
• Exempt foreign employment income (if applicable) [1]
• Certain trust distributions and family trust distribution tax amounts [1, 2]

How it compares:

• Assessable income is your total income before any deductions are subtracted.
• Taxable income is your assessable income minus your allowable work or business deductions.
• Income for MLS purposes takes your taxable income and adds back items like reportable fringe benefits and investment losses that were previously subtracted or not counted in taxable income. [1, 2]