The preparation of consolidated financial statements in accordance with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the consolidated financial statements and the amounts of revenues and expenses during the reporting period. Actual results could differ from these estimates. The Group bases its estimates on historical experience and various other factors believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying value of assets and liabilities that are not readily apparent from other sources. Management has made significant estimates in a variety of areas, including but not limited to allowance for doubtful accounts, useful lives and residual values of long-lived assets, impairment for long lived assets, valuation allowances for deferred tax assets, interest capitalization and certain assumptions used in the computation of share-based compensation and related forfeiture rates.

Accounts receivable represent those receivables derived in the ordinary course of business. The Group conducts credit evaluations of customers to whom credit terms are extended. The Group establishes an allowance for doubtful accounts mainly based on aging of the receivables and other factors surrounding the credit risk of specific customers. There is no allowance for doubtful accounts as of December 31, 2017 and 2018, based on the aging of the receivables and the Group’s assessment of the customers’ credit risk.

For investments classified as held-to-maturity securities, the Group evaluates whether a decline in fair value below the amortized cost basis is other-than-temporary in accordance with ASC 320. The other-than-temporary impairment loss is recognized in earnings equal to the excess of the investments' amortized cost basis over its fair value at the balance sheet date of the reporting period for which the assessment is made. No impairment loss in relation to its short-term investments was recorded for the year ended December 31, 2018.

The Group determines its allowance for doubtful accounts by actively monitoring the financial condition of its customers to determine the potential for any nonpayment of trade receivables. In determining its allowance for doubtful accounts, the Group also considers other economic factors, such as aging trends. The Group believes that its process of specific review of customers combined with overall analytical review provides an effective evaluation of ultimate collectability of trade receivables. Provisions for allowance for doubtful accounts are recorded as general and administrate expense in the consolidated statements of operations.

Inventories are stated at lower of cost or net realizable value. Costs are determined using weighted average costs. Costs comprise direct materials, direct labor and overhead costs incurred in bringing the inventories to their present location and condition. The Group writes down the cost of excess inventories to the estimated net realizable value based on historical and forecasted demand. Estimated net realizable value is measured as the estimated selling price of each class of inventory in the ordinary course of business less estimated costs of completion and disposal. The charges to inventory for the years ended December 31, 2016, 2017 and 2018 were nil, nil, and $851,008 from discontinued operations, respectively.

The Group reassesses the reasonableness of the estimates of useful lives and residual values of long-lived assets when events or changes in circumstances indicate that the useful lives and residual values of a major asset or a major category of assets may not be reasonable. Factors that the Group considers in deciding when to perform an analysis of useful lives and residual values of long-lived assets include, but are not limited to, significant variance of a business or product line in relation to expectations, significant deviation from industry or economic trends, and significant changes or planned changes in the use of the assets. The analysis will be performed at the asset or asset category with the reference to the assets’ conditions, current technologies, market, and future plan of usage and the useful lives of major competitors.

Interest expense incurred for construction of property, plant, and equipment is capitalized as part of the costs of such assets. The Group capitalizes interest to the extent that expenditures to construct an asset have occurred and interest costs have been incurred. Interest expense capitalized for the years ended December 31, 2016, 2017 and 2018 was $1,757,547, $47,507 and $1,203,547, respectively.

All land in the PRC is owned by the PRC government. The PRC government, according to PRC law, may sell the land use rights for a specified period of time. The Group’s land use rights in the PRC are stated at cost less recognized lease expenses. Lease expense is recognized over the term of the agreement on a straight-line basis. The Group recorded lease expenses of $517,448, $531,903 and $544,267, for the years ended December 31, 2016, 2017 and 2018, respectively.

The Group evaluates its long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset group may not be recoverable. Factors that the Group considers in deciding when to perform an impairment review include, but are not limited to significant under-performance of a business or product line in relation to expectations, significant negative industry or economic trends, and significant changes or planed changes in the use of the assets. An impairment analysis is performed at the lowest level of identifiable independent cash flows for an asset or asset group. The Group makes subjective judgments in determining the independent cash flows that can be related to a specific asset group based on the asset usage model and manufacturing capabilities. The Group measures the recoverability of assets that will continue to be used in the operations by comparing the carrying value of the asset group to the estimate of the related total future undiscounted cash flows. If an asset group’s carrying value is not recoverable through the related undiscounted cash flows, the impairment loss is measured by comparing the difference between the asset group’s carrying value and its fair value. The Group determines the fair value of an asset or asset group utilizing estimated future discounted cash flows and incorporates assumptions that it believes marketplace participants would utilize.

For the years ended December 31, 2016, 2017 and 2018, the Group recorded impairment losses for long-lived assets from discontinued operations of $198,689, $2,987,668 and $18,769,938,

respectively. No impairment loss for long-lived assets was recorded from continuing operations. The impairment losses of $198,689, $2,987,668 and $11,482,905 incurred in 2016, 2017 and 2018, respectively, were related to the polysilicon assets identified as non-transferrable and/or not able to be reutilized by its Xinjiang polysilicon manufacturing or expansion projects. The impairment losses

of $7,287,033 incurred in 2018 were related to the assets of discontinued wafer manufacturing operations.

As of January 1, 2018, the Company adopted ASU 2014-09

Revenue from Contracts with Customers - Topic 606

and all subsequent ASUs that modified ASC 606. The Company has elected to apply the ASU and all related ASUs retrospectively to each prior reporting period presented. The implementation of the guidance had no impact on the measurement or recognition of revenue of prior periods, however, additional disclosures have been added in accordance with the ASU.

The Group's revenue is all derived from the sale of polysilicon from the polysilicon segment, which is the only remaining segment after the discontinuation of the wafer business in September 2018. The sale of polysilicon is all in PRC and the Group's operations is in one PRC location, Xinjiang. Revenue cannot be disaggregated to a lower level or more than one categories to provide meaningful information. See Note 18 Segment Information. The Group recognizes sale of polysilicon at a point in time following the transfer of control of the products to the customers, which occurs upon delivery according to the terms of the underlying contracts. The Group's standalone selling prices are based on the prices charged to customers for the single performance obligation which is transfer of control of polysilicon upon delivery to the customers.

Variable consideration that could affect the Group's reported revenues is sales returns, which would be recorded as a reduction of revenue. Return rights of defective products are typically contractually limited, which allows sales returns within a period ranging from 3 to 30 days upon delivery. Sales returns have been nil for each reporting period presented. No warranties, incentives, or rebates arrangements has been offered to customers.

For majority of the sales arrangements, the Group requires payments prior to shipments. For

customers with trade credit granted on a short-term basis within 30 days, the Group records accounts receivable at the invoiced amount, net of an estimated allowance for doubtful accounts. As of December 31, 2017 and 2018, accounts receivable totaled $700,558 and $1,180,598, respectively. The Group did not record any allowance for doubtful accounts as of December 31, 2017 and 2018.

Advances from customers are to secure their polysilicon supply, which are applied against future purchases. Contract liabilities represent our obligations to transfer polysilicon for which we have received considerations from customers. The Group refers to contract liabilities as “advances from customers” on the consolidated financial statements and the related disclosures. The balance in the short-term and long-term advances from customers was $16.4 million and $17.5 million as of December 31, 2017 and 2018, respectively. Revenue recognized from the beginning advances from customers balance as of January 1, 2017 and January 1, 2018 was $7.2 million and $16.4 million, respectively.

We apply the new revenue standard requirements to a portfolio of contracts (or performance obligations) with similar characteristics for transactions where it is expected that the effects on the financial statements of applying the revenue recognition guidance to the portfolio would not differ materially from applying this guidance to the individual contracts (or performance obligations) within that portfolio. Therefore, we have elected the portfolio approach in applying the new revenue guidance.

Our revenue contracts provide for performance obligations that are fulfilled and transfer control to customers at point in time, involve the same pattern of transfer to the customer, and provide a right to consideration from our customers in an amount that corresponds directly with the value to the customer for the performance completed. Therefore, we recognize revenue in the amount to which we have a right to invoice.

We have made an accounting policy election to not assess whether promised products are performance obligations if they are immaterial in the context of the contract with the customer. If the revenue related to a performance obligation that includes products that are immaterial in the context of the contract is recognized before those immaterial products are transferred to the customer, then the related costs to transfer those products are accrued.

Cost of revenues consists of production related costs including costs of silicon raw materials, electricity and other utilities, consumables, direct labor, overhead costs, depreciation of property, plant and equipment, and manufacturing waste treatment processing fees. Cost of revenues does not include shipping and handling expenses, therefore the Group's cost of revenues may not be comparable to other companies which include such expenses in their cost of revenues.

Research and development expenses include materials and utilities consumed in research and development activities, payroll and related costs and depreciation of property and equipment associated with the research and development activities, which are expensed when incurred. The Group's research and development activities are mainly focused on technical improvement to improve the production volume, efficiency and lower unit cost.

The Group receives unrestricted cash subsidies from local government agencies. The government agencies, at their discretion, determine the amount of the subsidies with reference to fixed assets and land use right payments, value-added tax and income taxes paid, bank loan interest expenses paid or electricity consumed by the Group; The subsidies are unrestricted as to use and can be utilized by the Group in any manner it deems appropriate. The Group has utilized, and expects to continue to utilize, these subsidies to fund general operating expenses. The Group records unrestricted cash government subsidies as other operating income in the consolidated statements of operations. Unrestricted cash government subsidies received for the years ended December 31, 2016, 2017 and 2018 were $1,675,016, $3,704,144 and $13,136,922, respectively. Government grants related to fixed assets are recorded as long term liabilities and amortized on a straight-line basis over the useful life of the associated asset as an offset to depreciation expense. The Group did not receive any government grants related to fixed assets during the years ended December 31, 2016, 2017 and 2018.

Deferred income taxes are recognized for temporary differences between the tax bases of assets and liabilities and their reported amount in the consolidated financial statements, net operating loss carry-forwards and credits by applying enacted tax rates applicable to future years. Deferred tax assets are reduced by a valuation allowance when, in the opinion of management, it is more likely than not that some portion or all of the deferred tax assets will not be realized. Current income taxes are provided in accordance with the laws of the relevant taxing authorities. Deferred tax assets and liabilities are measured using enacted rates expected to apply to taxable income in which temporary differences are expected to be realized or settled. The effect on deferred tax assets and liabilities of changes in tax rates is recognized in the statement of operations in the period of the enactment of the change.

The Group recognizes share-based compensation in the consolidated statements of operations based on the fair value of equity awards on the date of the grant, with compensation expense recognized over the period in which the grantee is required to provide service to the Group in exchange for the equity award. The fair value of share options is determined using the Binomial option pricing model and the fair value of restricted share units ("RSUs") is determined with reference to the fair value of the underlying shares on the grant date. The Group has made an estimate of expected forfeiture and is recognizing compensation costs only for those equity awards expected to vest. The share-based compensation expenses have been categorized as either selling, general and administrative expenses or cost of sales, depending on the job functions of the grantees. For the years ended December 31, 2016, 2017 and 2018, the Group recognized share-based compensation expense of $2,702,089, $4,200,273 and $13,788,049, respectively, which was recognized in the statements of operations as follows:

The reporting currency of the Group is the United States dollar (“U.S. dollar”). The functional currency of the Group is the U.S. dollar. Monetary assets and liabilities denominated in other currencies other than the U.S. dollar are translated into U.S. dollar at the rates of exchange in effect at the balance sheet dates. Transactions dominated in currencies other than the U.S. dollar during the year are converted into U.S. dollar at the applicable rates of exchange prevailing when the transactions occur. Transaction gains and losses are recorded in the statements of operations.

The financial records of the Group’s PRC subsidiaries are maintained in Chinese Renminbi (“RMB”), which is their functional currency. Assets and liabilities are translated at the exchange rates at the balance sheet date. Equity accounts are translated at historical exchange rates. Revenues, expenses, gains and losses are translated at average rate of exchange prevailing during the periods presented. Translation adjustments are reported as cumulative translation adjustments and are shown as a separate component of other comprehensive income in the statement of changes in equity and comprehensive income.

The RMB is not a freely convertible currency. The State Administration for Foreign Exchange of People’s Republic of China, under the authority of the People’s Bank of China, controls the conversion of RMB into foreign currencies. The value of the RMB is subject to changes in central government policies and to international economic and political developments affecting supply and demand in the China foreign exchange trading system market. The Group’s aggregate amount of cash, cash equivalents and restricted cash denominated in RMB amounted to $66,433,887 and $81,476,636 as of December 31, 2017 and 2018, respectively.

The Group estimates fair value of financial assets and liabilities as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (also referred to as an exit price). The fair value measurement guidance establishes a hierarchy for inputs used in measuring fair value that gives the highest priority to observable inputs and the lowest priority to unobservable inputs. Valuation techniques used to measure fair value shall maximize the use of observable inputs.



Level 2—Valuation techniques in which significant inputs include quoted prices from active markets for assets or liabilities that are similar to the assets or liabilities being measured and/or quoted prices for assets or liabilities that are identical or similar to the assets or liabilities being measured from markets that are not active. Also, model-derived valuations in which all significant inputs and significant value drivers are observable in active markets are Level 2 valuation techniques.

When available, the Group measures the fair value of financial instruments based on quoted market prices in active markets, valuation techniques that use observable market-based inputs or unobservable inputs that are corroborated by market data. Pricing information the Group obtains from third parties is internally validated for reasonableness prior to use in the consolidated financial statements. When observable market prices are not readily available, the Group generally estimates fair value using valuation techniques that rely on alternate market data or inputs that are generally less readily observable from objective sources and are estimated based on pertinent information available at the time of the applicable reporting periods. In certain cases, fair values are not subject to precise quantification or verification and may fluctuate as economic and market factors vary and the Group’s evaluation of those factors changes. Although the Group uses its best judgment in estimating the fair value of these financial instruments, there are inherent limitations in any estimation technique. In these cases, a minor change in an assumption could result in a significant change in its estimate of fair value, thereby increasing or decreasing the amounts of the Group’s consolidated assets, liabilities, shareholders’ equity and net income or loss.

The Group’s financial instruments include cash and cash equivalents, restricted cash, short-term investments, accounts receivable, notes receivable, amount due from related parties, accounts payable, other current liabilities, payables for purchase of property, plant and equipment, amounts due to related parties and bank borrowings. The carrying amounts of these short-term financial instruments approximate their fair values due to the short-term maturity of these instruments.

The Group’s long-term bank borrowing consists of floating rate loans. The fair value of long-term borrowings is measured using discounted cash flow technique based on current rates for comparable loans on the respective valuation date and is therefore considered a level 2 measurement. The long-term bank borrowings approximate their fair values because market interest rates have not fluctuated significantly since the commencement of loan contracts signed.

The Group classified the ownership interest in the consolidated entity held by a party other than the Group to non-controlling interest in the consolidated financial statements. It also reported the consolidated net income at amounts that include the amounts attributable to both the parent and the non-controlling interest on the face of the Consolidated Statements of Operations. Xinjiang Daqo Investment's equity interests in Xinjiang Daqo was presented as a non-controlling interest before it was acquired by Xinjiang Daqo in December 2018. The non-controlling interest was $2,792,480 and nil as of December 31, 2017 and 2018, respectively.

On February 17, 2016, Xinjiang Daqo entered into an agreement to invest in Syned Fire Safety Service Co., Ltd. ("Syned Fire Safety Services"), a company engaging in fire safety activities. Pursuant to the agreement, Xinjiang Daqo contributed a capital investment of $581,581 in cash, which represents 15.29% of the share capital of Syed Fire Safety Services and holds one of the seven seats on the board of the director of the investee. In October 2017, Xinjiang Daqo contributed an additional capital investment of $63,793 and its percentage of ownership remained the same. The Group accounts for the investment using the cost method as the Group is unable to exercise significant influence on the investee.

The Group reviews its investment in Syed Fire Safety Service to determine whether a decline in fair value below the carrying value, if any, is other-than-temporary. No impairment loss occurred during the years ended December 31, 2016, 2017 and 2018. Although assumptions used in estimates of fair value of the investment in Syed Fire Safety Service are management best estimates, such assumptions are, by nature, highly judgmental and may vary significantly from actual results.

In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows, Restricted Cash, which clarifies guidance on the classification and presentation of restricted cash in the statement of cash flows. ASU 2016-18 becomes effective for the Group on January 1, 2018. As a result of the adoption of the ASU as of December 31, 2018, the Group has changed its presentation to combine restricted cash with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statements of cash flows.

In January 2016, the FASB issued ASU 2016-01, Financial Instruments - Overall: Recognition and Measurement of Financial Assets and Financial Liabilities, which requires that most equity investments be measured at fair value, with subsequent changes in fair value recognized in net income. The ASU also impacts financial liabilities under the fair value option and the presentation and disclosure requirements for financial instruments. In addition, the FASB clarified guidance related to the valuation allowance assessment when recognizing deferred tax assets resulting from unrealized losses on available-for-sale debt securities. Entities will have to assess the realizability of such deferred tax assets in combination with the entities other deferred tax assets. ASU 2016-01 is effective for fiscal years beginning after December 15, 2017 and for interim periods within that reporting period. The Group adopted the ASU for the year ended December 31, 2018 and has already considered the impact on its consolidated financial statements and related disclosures and the effects upon adoption are not material.

In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows, Restricted Cash, which clarifies guidance on the classification and presentation of restricted cash in the statement of cash flows. ASU 2016-18 becomes effective for the Group on January 1, 2018. As a result of the adoption of the ASU as of December 31, 2018, the Group has included amounts generally described as "restricted with cash and cash equivalents" when reconciling the beginning-of-period and end-of-period total amounts shown on the statements of cash flows, and it did not have any other material impact on the Group's consolidated financial statements.

In February 2016, the FASB issued ASU 2016-02, Leases. This ASU requires lessees to recognize right-of-use assets and liabilities for operating leases, initially measured at the present value of the lease payments, on the balance sheet. In addition, it requires lessees to recognize a single lease cost, calculated so that the cost of the lease is allocated over the lease term, generally on a straight-line basis. The definition of a lease has been revised in regards to when an arrangement conveys the right to control the use of the identified asset under the arrangement which may result in changes to the classification of an arrangement as a lease. The ASU expands the disclosure requirements of lease arrangements. This ASU is effective for fiscal years and interim periods within those years beginning after December 15, 2018, and early adoption is permitted. In July 2018, the FASB issued ASU 2018-11, Leases (Topic 842): Targeted Improvements, which provided an optional transition method to apply the new lease requirements through a cumulative-effect adjustments in the period of adoption. The Group expects to adopt the standard in the first quarter of 2019using the modified retrospective method and will not restate comparative periods, as permitted by the standard. In addition, the Group will elect the transition practical referred to as the “package of three”, that must be taken together and allows entities to (1) not reassess whether existing contracts contain leases, (2) carryforward the existing lease classification, and (3) not reassess initial direct costs associated with

existing leases. As of December 31, 2018, the Group has $11,729 of future minimum operating lease commitments that are not currently recognized on its consolidated balance sheets (Note 17). Therefore, the Group does not expect material changes to its consolidated financial statements.

In June 2016, the FASB issued ASU 2016-13, Credit Losses, Measurement of Credit Losses on Financial Instruments. This ASU significantly changes how entities will measure credit losses for most financial assets and certain other instruments that are not measured at fair value through net income. The standard will replace today’s incurred loss approach with an expected loss model for instruments measured at amortized cost. Entities will apply the standard’s provisions as a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective. This ASU is effective for public entities for annual and interim periods beginning after December 15, 2019. Early adoption is permitted for all entities for annual periods beginning after December 15, 2018, and interim periods therein. The Group is in the process of evaluating the impact on its consolidated financial statements upon adoption.

In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement, which changes certain disclosure requirements, including those related to Level 3 fair value measurements. The standard will be effective for annual reporting periods beginning after December 15, 2019. Early adoption is permitted. The Group is evaluating the impact on its consolidated financial statements upon adoption.