As your stay in Singapore for the first year was less than 183 days, you were taxed at the flat rate of 15% on your employment income. However if you were to stay / work in Singapore for 3 consecutive years of assessment, we will consider to revise your assessment to tax you at the resident rate even if your first and last year in Singapore is less than 183 days. You need to send the relevant documents to prove the duration of your stay or employment in Singapore in order for us to review your assessment.