Section 51C of the Inland Revenue Ordinance requires every person carrying on a trade, profession or business in Hong Kong to keep sufficient business records, either in English or Chinese, to enable the assessable profits of your business to be readily ascertained. You must keep such records for at least 7 years. Failure to do so may render you liable to a maximum penalty of HK$100,000.

The records prescribed in the Ordinance include:

1.	books of accounts recording receipts and payments, or income and expenditure;
2.	underlying documentation necessary to verify the entries in the books of account, such as vouchers, bank statements, invoices, receipts and other relevant papers;
3.	records of the assets and liabilities of your business;
4.	day by day record of all sums of money received and expended by your trade, profession or business together with supporting details of the receipts or payments;
5.	where the business involves dealing in goods –
	(a)	record of all goods purchased and all goods sold. Copies of the invoices for the transactions must show goods, and the buyers and sellers, in sufficient detail to enable the Commissioner to readily verify the quantities and values of the goods and the identities of the sellers and buyers;
	(b)	statements (including quantities and values) of trading stock on hand at the end of the accounting year together with stocktaking records from which the trading stock statements have been prepared;
6.	where the business involves the provision of services –
	(a)	records of all services provided in sufficient detail to enable the Commissioner to readily verify the entries in the business’s day to day record of all monies received and expended.

Source：Hong Kong Inland Revenue Department’s website

- https://www.ird.gov.hk/eng/tax/bus_rke.htm
- https://www.ird.gov.hk/eng/pdf/51c_pam.pdf