有關 Personal Assessment 一問

Joint assessment can be advantageous for a married couple if the assessable income of one spouse is less than his or her tax allowance. Under the invidual assessment, such tax allowance could not be offset by the other party.

If this is the case, you and your spouse should each complete a Tax Return - Individuals (B.I.R. 60) and elect joint assessment in part 4.4 and both you and your spouse have to sign in part 9 of each tax return. The election must be made on a yearly basis.
Under joint assessment, the incomes of the couples will be aggregated and the married person’s allowance or other allowances that the couple is eligible for will be deducted from the couple’s joint total income. This could result in some tax savings, and a notice of assessment will be issued. However, if joint assessment does not result in less tax, each spouse will receive a separate notice of assessment.

http://www.gov.hk/en/residents/taxes/salaries/salariestax/jointassessment.htm

http://www.ird.gov.hk/chi/pdf/ind_jac.pdf

稅務制度原則上以公平及要求高收入者多付稅。你如果有於2008年10月下旬去過中央圖書館睇稅務局舉辦「稅務六十年」你會比較清楚。在原則上嚟講已婚者係計家庭收入，而未婚者計個人收入，所以納稅人必須清楚表達自己以個體身份定係家庭身份作為評稅標準！