6.	Income Tax

Cayman Islands

Zai Lab Limited and ZLIP Holding Limited are incorporated in the Cayman Islands. Under the current laws of the Cayman Islands, Zai Lab Limited and ZLIP Holding Limited are not subject to tax on income or capital gain. Additionally, the Cayman Islands does not impose a withholding tax on payments of dividends to shareholders.

British Virgin Islands Taxation

ZL Capital Limited is incorporated in the British Virgin Islands. Under the current laws of the British Virgin Islands, ZL Capital Limited is not subject to income tax.

Australia

Zai Lab (AUST) Pty., Ltd. is incorporated in Australia and is subject to corporate income tax at a rate of 30%. Zai Lab (AUST) Pty., Ltd. has no taxable income for all periods presented, therefore, no provision for income taxes is required.

Hong Kong

Zai Lab (Hong Kong) Limited is incorporated in Hong Kong. Companies registered in Hong Kong are subject to Hong Kong profits tax on the taxable income as reported in their respective statutory financial statements adjusted in accordance with relevant Hong Kong tax laws. The applicable tax rate is 16.5% in Hong Kong. For the years ended December 31, 2015, 2016 and 2017, Zai Lab (Hong Kong) Limited did not make any provisions for Hong Kong profit tax as there were no assessable profits derived from or earned in Hong Kong for any of the periods presented. Under the Hong Kong tax law, Zai Lab (Hong Kong) Limited is exempted from income tax on its foreign-derived income and there are no withholding taxes in Hong Kong on remittance of dividends.

PRC

Zai Lab (Shanghai) Co., Ltd., Zai Lab (Suzhou) Co., Ltd., and Zai Biopharmaceutical (Suzhou) Co., Ltd. are subject to the statutory rate of 25% in accordance with the Enterprise Income Tax law (the "EIT Law").

No provision for income taxes has been required to accrue because the Company and all of its owned subsidiaries are in cumulative loss positions for all the periods presented.

Loss before income taxes consists of:

	Year ended December 31,
	2015		2016		2017
	$		$		$
Cayman		2,036,806		2,454,660		3,886,673
BVI		—		—		8,375
PRC		4,938,688		26,111,094		40,971,742
HK		9,869,007		8,010,908		6,240,462
AUST		1,177,236		935,550		(723,076	)
		18,021,737		37,512,212		50,384,176

Reconciliations of the differences between the PRC statutory income tax rate and the Group’s effective income tax rate for the years ended December 31, 2015, 2016 and 2017 are as follows:

	Year ended December 31,
	2015			2016			2017
	$			$			$
Statutory income tax rate		25	%		25	%		25	%
Share-based compensations		(3.68	%)		(2.92	%)		(3.27	%)
Non-deductible expenses		(7.19	%)		(1.59	%)		(0.79	%)
Effect of different tax rate of subsidiary operation in other jurisdictions		(7.15	%)		(3.33	%)		(3.06	%)
Changes in valuation allowance		(6.98	%)		(17.16	%)		(17.88	%)
Effective income tax rate		—			—			—

The principal components of the deferred tax assets and liabilities are as follows:

	Year ended December 31,
	2015			2016			2017
	$			$			$
Deferred tax assets:
Depreciation of property and equipment, net		2,415			3,892			5,964
Accrued expenses		72,408			—			—
Government grants		16,025			166,336			187,762
Net operating loss forwards		1,729,009			8,086,361			17,075,387
Less: valuation allowance		(1,819,857	)		(8,256,589	)		(17,269,113	)
Deferred tax assets, net		—			—			—

The Group considers positive and negative evidence to determine whether some portion or all of the deferred tax assets will be more likely than not realized. This assessment considers, among other matters, the nature, frequency and severity of recent losses and forecasts of future profitability. These assumptions require significant judgment and the forecasts of future taxable income are consistent with the plans and estimates the Group is using to manage the underlying businesses. Valuation allowances are established for deferred tax assets based on a more likely than not threshold. The Group’s ability to realize deferred tax assets depends on its ability to generate sufficient taxable income within the carry forward periods provided for in the tax law. In 2016 and 2017, the Group has determined that the deferred tax assets on temporary differences and net operating loss carry forwards are related to certain subsidiaries, for which the Group is not able to conclude that the future realization of those net operating loss carry forwards and other deferred tax assets are more likely than not. As such, it has fully provided valuation allowance for the deferred tax assets as of December 31, 2016 and 2017. Amounts of operating loss carry forwards were $7,969,098, $34,716,071 and $72,137,289 for the year ended December 31, 2015, 2016 and 2017, respectively, which are expected to expire from 2019 to 2022.

Movement of the valuation allowance is as follows:

	2016			2017
	$			$
Balance as of January 1,		(1,819,857	)		(8,256,589	)
Additions		(6,436,732	)		(9,012,524	)
Balance as of December 31,		(8,256,589	)		(17,269,113	)

Uncertainties exist with respect to how the current income tax law in the PRC applies to the Group’s overall operations, and more specifically, with regard to tax residency status. The EIT Law includes a provision specifying that legal entities organized outside of the PRC will be considered residents for Chinese income tax purposes if the place of effective management or control is within the PRC. The implementation rules to the EIT Law provide that non-resident legal entities will be considered PRC residents if substantial and overall management and control over the manufacturing and business operations, personnel, accounting and properties, occurs within the PRC. Despite the present uncertainties resulting from the limited PRC tax guidance on the issue, the Group does not believe that the legal entities organized outside of the PRC within the Group should be treated as residents for EIT Law purposes. If the PRC tax authorities subsequently determine that the Company and its subsidiaries registered outside the PRC should be deemed resident enterprises, the Company and its subsidiaries registered outside the PRC will be subject to the PRC income taxes, at a rate of 25%. The Group is not subject to any other uncertain tax position.