The basic test for HK profits tax chargeability is whether the person carries on a trade, profession or business in Hong Kong and profit arises from such a trade, profession or business and that profit is sourced in Hong Kong.

繳納利得稅的基本驗證法：
（a）該名人士必須在香港經營行業，專業或業務;
（b）應課稅利潤必須來自該名士士在香港所經營的行
業，專業或業務;以及
（c）利潤必須在香港產生或得自香港。

是否經營行業，專業或業務
it is often difficult to determine whether an isolated transaction or a series of transactions constitutes a ‘trade’ or not, and the commonly used criteria are the so-called ‘badges of trade’. i.e. the original intention of acquisition, the funding arrangement, frequency of similar transaction, any supplementary work done on the property, length of holding period and the circumstances leading to the disposal.
比方說購買房地產的時候是預計短期內房價會飆升，使用短期借款資金來購買，頻繁地進行買賣，在賣出去前做一些改良以便賣得更好，持有時間短，除了可觀的利潤外沒有其他促成銷售的理由等等當然不會限定就這幾項，每個案例會綜合考慮所以經常看到這句話。：

“each case should be assessed on its own merits.”

舉個例子：題目太長，摘一小部分
Generally, if the property has been let for rental income since acquisition, it would likely be accepted as an investment property unless other factors prove otherwise.
However, in the case of Property A, the fact that the property has only been let on a short-term basis, and that the second lease was not proved in written contract would not be convincing enough to prove that the intention of holding the property was for long-term investment purposes. In addition, the property was initially listed at the property agency for sale immediately after the acquisition. Coupled with the fact that 90% of the acquisition cost was financed by bank borrowing, it is very likely that the profit would be regarded as trading profit and chargeable to profits tax.

Property B was occupied by Mr Ko himself since acquisition during the period from July 2011 to September 2011.
Like Property A, the question of whether the profit is taxable to profits tax arises.
Apart from the general principles of ‘badges of trade’, it is also relevant to consider whether the intention of Mr Ko has changed at any time during the year.

注意：除了'交易徽章'還有個改變意向的問題，即購入的時候是為了長期持有，但出售前的某個時點，長期持有目的改變為短期盈利了。

是否在香港經營行業，專業或業務
There have been numerous cases debating the factors that determine the place where a business is carried on. In general, the IRD’s practice is to look at the place of the company’s effective management and control, which usually refers to the place where the board of directors meet and make decisions, and where the company’s day-to-day activities are conducted.

利潤是否得自香港產

There is no statutory or comprehensive guidance under the IRO as to how the source of profits is to be determined. Based on case law and DIPN 21 (revised 2009), the broad guiding principle is the so-called ‘operation test’, (that one looks to see what the taxpayer has done to earn the profit and where he has done it)

舉個例子：

However, if BVI co is carrying on business in Hong Kong, the profit, if any, arising from the sale of the 50% shareholding in HK Business would need to be reported to the Inland Revenue Department (IRD); but it may be claimed as a non-taxable profit on the basis that it arises from a capital transaction given that BVI co has been holding the shares in Business for investment purposes over a number of years, it is probable [possible] that the capital profit argument may be sustained, unless there is a change of intention of BVI co from holding the shares for a capital investment purpose to a profit-making trading purpose

決定權在IPD，當然納稅人可以lodge objection or appeal.

利潤是否得自香港
對買賣上市公司股票，看股票交易所的位置。非上市公股票，還是‘operation test
對服務業來說，一般是看勞務提供地。
對生產企業來說，一般是看生產運行的地方。
這里有個減免規定是對來料加工的：只對生產所得的50％征所得稅：
The IRD provides a concession where a Hong Kong manufacturing business enters into a processing arrangement contract processing’. with a Mainland entity, under which the Mainland entity provides the factory premises, the land and labour while the Hong Kong manufacturing business provides the raw materials, technical know-how, management, production skills, design, skilled labour, training and supervision for the local labour and the manufacturing plant and machinery.

The Mainland entity is responsible for processing the goods, for which it is paid a processing fee by the Hong Kong manufacturing business. This kind of arrangement is called ‘contract processing’. Strictly, the profits of the Hong Kong manufacturing business should be fully taxable, [in the Department view, the HK company operations in China complement its operations in HK]
as the manufacturing is carried out by an independent contractor and the question of apportionment does not arise. However, recognising that the Hong Kong manufacturing business is involved in the manufacturing activities on the Mainland, an apportionment of profits on a 50:50 basis is usually accepted.

The concession under paragraph 16 of DIPN No. 21 is only available to ‘contract processing’ and not to ‘import processing’
進料加工不適用此規定。

另處，銀行，保險公司,,航空，陸地，江河貨客有特別的規定。

再補充一點：香港有個視同利潤得自香港的反避稅規定。
舉例
s.20 of IRO
This section is designed to counteract the diversion of profits from Hong Kong to a closely connected non-resident. Since HK Co carries on business with BVI Co which is closely connected to HK Co, and the sale of the equipment gives rise to an overly significant tax deduction of equipment cost to HK Co , s.20(2) would apply to deem BVI Co to have carried on business in Hong Kong through HK Co. As a result, an assessment would be issued to tax the profit of BVI Co in the name of HK Co as an agent.