22. COMMITMENTS AND CONTINGENCIES Operating lease commitments As of December 31, 2014, the Group had future minimum lease payments under non-cancellable operating leases with initial terms in excess of one year as follows: US$ 2015 10,936 2016 7,378 2017 2,982 2018 20 2019 and thereafter - 21,316 Payments under operating leases are expensed on a straight-line basis over the periods of the respective leases. The Group's lease arrangements have no renewal options, rent escalation clauses, restrictions or contingent rents and are all conducted with third parties, except for the building leased from a related party as disclosed in Note 20. For the years ended December 31, 2012, 2013 and 2014, total rental expenses for all operating leases were US$ 12,540 , US$ 12,915 and US$ 14,302 , respectively. Variable interest entity structure In the opinion of management, (i) the ownership structure of the Company and the PRC Domestic Entities is in compliance with existing PRC laws and regulations; (ii) the contractual arrangements with the PRC Domestic Entities and their shareholders are valid, binding and enforceable, and will not result in any violation of PRC laws or regulations currently in effect; and (iii) the Group's business operations are in compliance with existing PRC laws and regulations in all material respects. However, there are substantial uncertainties regarding the interpretation and application of current and future PRC laws and regulations. Accordingly, the Company cannot be assured that PRC regulatory authorities will not ultimately take a contrary view to its opinion. If the current ownership structure of the Group and its contractual arrangements with the PRC Domestic Entities are found to be in violation of any existing or future PRC laws and regulations, the Group may be required to restructure its ownership structure and operations in the PRC to comply with the changing and new PRC laws and regulations.If a finding were made by PRC authorities, under existing law and regulations or under the draft Fo