X0306 4 2018-03-01 0 0001418819 Iridium Communications Inc. IRDM 0001229996 FITZPATRICK THOMAS C/O IRIDIUM COMMUNICATIONS INC. 1750 TYSONS BOULEVARD, SUITE 1400 MCLEAN VA 22102 1 1 0 0 Chief Financial Officer Common Stock 2018-03-01 4 F 0 4145 11.85 D 185537 D Common Stock 2018-03-01 4 A 0 15832 0.00 A 201369 D Common Stock 2018-03-01 4 F 0 2382 11.85 D 198987 D Common Stock 2018-03-01 4 A 0 16877 0.00 A 215864 D Common Stock 2018-03-04 4 A 0 35761 0.00 A 251625 D Common Stock 2018-03-04 4 F 0 10764 11.50 D 240861 D The transaction reported represents the withholding of shares by the issuer to satisfy the reporting person's tax withholding obligations in connection with the non-reportable vesting and settlement of restricted stock units. These shares are represented by restricted stock units. Each restricted stock unit represents a contingent right to receive one share of common stock of the issuer. Of the shares underlying this restricted stock award, one-half vested on March 1, 2018 and the remainder will vest on March 1, 2019, subject to the reporting person's continuous service with the issuer as of the vesting date. The transaction reported represents the withholding of shares by the issuer to satisfy the reporting person's tax withholding obligations in connection with the vesting and settlement of the restricted stock unit award reported in footnote (2) herein. These shares are represented by restricted stock units. Each restricted stock unit represents a contingent right to receive one share of common stock of the issuer. Of the shares underlying this restricted stock unit award, 25% shall vest on March 1, 2019 and the remainder shall vest in equal quarterly installments thereafter on each June 1, September 1, December 1 and March 1, so that all shares of common stock shall be vested as of March 1, 2022, subject to the reporting person's continuous service with the issuer as of each such vesting date. Represents the vested portion of a performance-based restricted stock unit award based on the issuer's satisfaction of certain performance criteria. In light of the performance-based vesting conditions of the award, such award was not reportable under Section 16 until vesting was determined, which occurred on March 4, 2018. The transaction reported represents the withholding of shares by the issuer to satisfy the reporting person's tax withholding obligations in connection with the vesting and settlement of the restricted stock unit award reported in footnote (5) herein. /s/Brian Leaf, Attorney-in-Fact 2018-03-05