If you make HK$1,300,000 a year living in Hong Kong, you will be taxed HK$195,500. That means that your net pay will be HK$1,104,500 per year, or HK$92,042 per month. Your average tax rate is 15.0% and your marginal tax rate is 17.0%. This marginal tax rate means that your immediate additional income will be taxed at this rate. For instance, an increase of HK$100 in your salary will be taxed HK$17, hence, your net pay will only increase by HK$83.
A HK$1,000 bonus will generate an extra HK$830 of net incomes. A HK$5,000 bonus will generate an extra HK$4,150 of net incomes.