Zai Lab Limited (ZLAB) SC 13G/A Zai Lab Ltd

 Exhibit 99.1

JOINT FILING AGREEMENT

PURSUANT TO RULE 13d-1(k)

The undersigned acknowledge and agree that the foregoing statement on Schedule 13G is filed on behalf of each of the undersigned and that all subsequent amendments to this statement on Schedule 13G shall be filed on behalf of each of the undersigned without the necessity of filing additional joint acquisition statements. The undersigned acknowledge that each shall be responsible for the timely filing of such amendments, and for the completeness and accuracy of the information concerning him or it contained therein, but shall not be responsible for the completeness and accuracy of the information concerning the others, except to the extent that he or it knows or has reason to believe that such information is inaccurate.

Dated: January 31, 2020

The Segantii Asia-Pacific Equity Multi-Strategy Fund

By:          /s/ Niral Harish Maru                                          

Name: NIRAL HARISH MARU

Title: Authorized Signatory

Segantii Capital Management (Cayman) Limited

By:          /s/ Niral Harish Maru                                          

Name: NIRAL HARISH MARU

Title: Head of Legal and Compliance

Segantii Capital Management Limited

By:          /s/ Niral Harish Maru                                          

Name: NIRAL HARISH MARU

Title: Head of Legal and Compliance

Segantii Capital Management (UK) Limited

By:          /s/ Niral Harish Maru                                          

Name: NIRAL HARISH MARU

Title: Director