IAMGOLD Completes Acquisition Of Northern Superior; Shareholders Receive 0.0991 IAMGOLD Shares Plus C$0.19 Cash Per Share And Distribution Of ONGold Resources Shares

All monetary amounts are expressed in U.S. dollars, unless otherwise indicated.

Toronto, Ontario--(Newsfile Corp. - December 19, 2025) - IAMGOLD Corporation (NYSE:IAG) (TSX:IMG) ("IAMGOLD" or the "Company") is pleased to announce that the Company has completed the previously announced arrangement (the "Transaction") with Northern Superior Resources Inc. (TSXV:SUP) (OTCQB:NSUPF) (GR: D9M1) ("Northern Superior"), pursuant to which IAMGOLD acquired all of the issued and outstanding common shares of Northern Superior (the "NSUP Shares") by way of a plan of arrangement under Division 5 of Part 9 of the Business Corporations Act (British Columbia).

"With the completion of the acquisition of Northern Superior and its assets, IAMGOLD's Nelligan Mining Complex in the Chibougamau-Chapais region of Quebec is now among the largest pre-production gold projects in Canada," said Renaud Adams, President and Chief Executive Officer of IAMGOLD. "We look forward to accelerating our exploration program in the region with a goal of further expansion and extension of the mineralization at Nelligan, Philibert and Monster Lake, as we look to continue to grow the mineralization and advance a project that complements both the scale and timing of our Côté Gold Mine and its forthcoming expansion."

As a result of the completion of the Transaction and the acquisition by IAMGOLD of all of the NSUP Shares, Northern Superior became a wholly-owned subsidiary of IAMGOLD. Former Northern Superior shareholders are now entitled to receive, in exchange for each NSUP Share held immediately prior to the effective time of the Transaction, a combination of (i) 0.0991 of an IAMGOLD common share and (ii) C$0.19 in cash. The Transaction also included a concurrent distribution to Northern Superior's shareholders of all the common shares in the capital of ONGold Resources Ltd. previously held by Northern Superior.