The gains from stock options are part of employment income. The tax rate charged depends on the amount of income an individual earns and whether the individual is regarded as a tax resident or non-resident in Singapore. If an individual is a tax-resident, then his income will be taxed at graduated rates from 4% to 22%. If an individual is a non-resident, then his income will be taxed at 15% or resident rates, whichever gives rise to higher tax.