Osisko Metals Incorporated (TSX: OM) (OTCQX: OMZNF) (FRANKFURT:0B51) is pleased to announce new analytical results from the ongoing 2026 drill program at the Gaspé Copper Project, located in the Gaspé Peninsula of Eastern Québec. Results are presented below (see Table 1), and include 38 mineralized intercepts from 15 drill holes. Reported “infill” intercepts are located within the 2026 MRE model (see April 14, 2026 news release), focused on upgrading Inferred Mineral Resources to Measured or Indicated categories, as applicable. “Expansion” intercepts are located outside the 2026 MRE model and comprise either i) in-pit expansion, which offers potential to convert in-pit waste into additional resources within the 2026 MRE Whittle pit; or ii) out-of-pit expansion, consisting of mineralization located outside the 2026 MRE Whittle pit, which may potentially lead to the definition of new resources. Some of the reported intercepts may have contiguous shallower infill as well as deeper in-pit expansion. Maps showing hole locations are available at www.osiskometals.com.

Osisko Metals Chief Executive Officer Robert Wares commented: “Today’s results, particularly drill holes 30-1270 and 30-1272, show once again strong results from the southern end of the 2026 MRE model. Furthermore, drill hole 30-1260, which is the most southerly hole drilled to date at Needle Mountain (out-of-pit expansion), located approximately 400 metres southwest of the current 2026 MRE pit boundary, returned 121 metres averaging 0.42% Cu at the level of the B and C Zones, indicating the system continues to be well mineralized and open to the south.”

Highlights

• 314.0 metres averaging 0.44% Cu (infill) in DDH 30-1272; includes 9.0 metres averaging 3.23% Cu and 16.7 g/t Ag
• 240.5 metres averaging 0.44% Cu (infill) in DDH 30-1270
• 552.5 metres averaging 0.30% Cu (infill) in DDH 30-1269
• 142.6 metres averaging 0.34% Cu (infill) in DDH 30-1274
• 121.5 metres averaging 0.42% Cu (out-of-pit expansion) in DDH 30-1260
• 87.5 metres averaging 0.48% Cu (out-of-pit expansion) in DDH 30-1268; includes 10.7 metres averaging 1.98% Cu and 9.0 g/t Ag
• 85.5 metres averaging 0.42% Cu (out-of-pit expansion) in DDH 30-1265

Table 1: Infill and Expansion Drilling Results

* See explanatory notes below on copper equivalent values and Quality Assurance/Quality Controls.
** Infill refers to intercepts within the current MRE model; Expansion 1 refers to in-pit intercepts outside of the current MRE model; Expansion 2 refers to out-of-pit intercepts outside of the current MRE model. “Both” indicates drill holes that havecontiguous shallower infill as well as deeper in-pit expansion intercepts.

Additional comments

Drill holes 30-1260 and 30-1268 are located on the north flank of Needle Mountain near its peak, with 30-1260 being the most southerly hole drilled to date on Needle Mountain. Hole 30-1260 was a vertical hole that intersected 121.5 metres averaging 0.42% Cu and 2.39 g/t Ag at the level of the B and C Zone skarns, including the intervening porcellanites. Drill hole 30-1268 is a westerly inclined hole that intersected 87.5 metres averaging 0.48% Cu and 2.71 g/t Ag, also at the level of the B and C Zone skarns. Both holes indicate that the mineralized system at Needle Mountain remains open to the south.

Drill hole 30-1266 is a westerly inclined hole located along the northeast margin of the Needle Mountain pit. It intersected two short intervals of mineralization, including 33.0 metres averaging 0.41% Cu and 2.63 g/t Ag.

Drill hole 30-1265 is a vertical hole located just south of the southern limit of the 2026 MRE model. It intersected four intervals of mineralization, 12.4 to 85.5 metres long, averaging 0.27 to 0.83% Cu and 2.43 to 7.30 g/t Ag, the last interval representing a significant out-of-pit expansion.

Drill holes 30-1262, 30-1270 and 30-1272 are all infill holes located near the southern margin of the 2026 MRE model. Hole 30-1262 is westerly inclined that expanded the mineralized envelope to the west, while 30-1270 and 30-1272 drilled through pillars of both the B Zone and C Zone underground workings, returning continuous well-mineralized intervals of 240.5 and 314.0 metres, respectively, averaging 0.44% Cu.

Drill holes 30-1261, 30-1263, 30-1264, 30-1267, 30-1269, 30-1271 and 30-1274 are all vertical to near-vertical infill holes located on the south flank of Copper Mountain. All returned multiple mineralized intervals that graded in a range of 0.12% to 0.40% Cu, all within values anticipated from the 2026 MRE model.

Mineralization at Gaspé Copper is of porphyry copper/skarn type and occurs as disseminations and stockworks of chalcopyrite with pyrite or pyrrhotite and minor bornite and molybdenite. One prograde and at least five retrograde vein/stockwork mineralizing events have been recognized at Copper Mountain, which overprint earlier, stratiform, carbonate replacement skarn and porcellanite-hosted mineralization throughout the Gaspé Copper system. Porcellanite is a historical mining term used to describe bleached, pale green to white potassic-altered hornfels. Subvertical stockwork mineralization dominates at Copper Mountain whereas prograde bedding-parallel mineralization, which is mostly stratigraphically controlled, dominates in the area of lower Copper Mountain, Needle Mountain, Needle East, and Copper Brook. High molybdenum grades (up to 0.5% Mo) were locally obtained in both the C Zone and E Zone skarns away from Copper Mountain.

The 2022 to 2024 Osisko Metals drill programs were focused on defining open-pit resources within the Copper Mountain stockwork mineralization (see May 6, 2024 MRE press release). Extending the resource model south of Copper Mountain into the poorly-drilled prograde skarn/porcellanite portion of the system subsequently led to a significantly increased resource, mostly in the Inferred category (see November 14, 2024 MRE press release), and additional drilling in 2025 led to an additional significant increase in resources, mostly in the Measured and Indicated categories (see April 14, 2026 MRE press release).

The current drill program is designed to convert the bulk of the remaining 2026 MRE Inferred resources to Measured and Indicated categories, as well as test the expansion of the overall resource laterally to the west, and to the south/southwest towards Needle East and Needle Mountain respectively.

Table 2: Drill hole locations

Explanatory note regarding copper-equivalent grades

Copper Equivalent grades are presented for illustrative purposes only to express the combined value of copper, molybdenum, and silver as a single copper grade. CuEq grades are calculated using long-term metal prices of US$4.50/lb copper, US$20.00/lb molybdenum, and US$45.00/oz silver, and incorporate assumptions for metallurgical recoveries, payable metal factors, smelting and refining charges, transportation costs, and royalties. Hence the CuEq calculation is essentially based on net smelter return (NSR) values. NSR for each metal is estimated by applying metallurgical recoveries, payable factors, metal prices, and applicable smelting, refining, transportation, and penalty charges to the in-situ metal grades. CuEq grades are derived using a linear regression relationship established between copper grade and copper NSR, and then calculated by substituting total NSR (Cu + Mo + Ag) for copper NSR in the regression equation. The simplified formula is expressed as CuEq (%) = Cu (%) + 3.40327 × Mo (%) + 0.00008 × Ag (g/t).

Qualified Person

The scientific and technical content of this news release has been reviewed and approved by Mr. Bernard-Olivier Martel, P. Geo. (OGQ 492), an independent “qualified person” as defined by National Instrument 43-101 – Standards of Disclosure for Mineral Projects.

Quality Assurance / Quality Control

Mineralized intervals reported herein are calculated using an average 0.12% CuEq lower cut-off over contiguous 20-metre intersections (shorter intervals as the case may be at the upper and lower limits of reported intervals). Intervals of 10 metres or less are generally not reported unless considered material. True widths are estimated at 80 – 90 % of the reported core length intervals.

Osisko Metals adheres to a strict QA/QC program for core handling, sampling, sample transportation and analyses, including insertion of blanks and standards in the sample stream. Drill core is drilled in HQ or NQ diameter and securely transported to its core processing facility on site, where it is logged, cut and sampled. Samples selected for assay are sealed and shipped to ALS Canada Ltd.’s preparation facility in Sudbury. Sample preparation details (code PREP-31DH) are available on the ALS Canada website. Pulps are analyzed at the ALSCanada Ltd. facility in North Vancouver, BC. All samples are analyzed by fouracid digestion followed by both ICP-AES and ICP-MS for Cu, Mo and Ag.

About Osisko Metals

Osisko Metals Incorporated is a Canadian exploration and development company creating value in the critical metals sector, with a focus on copper and zinc. The Company acquired a 100% interest in the past-producing Gaspé Copper mine from Glencore Canada Corporation in July 2023. The Gaspé Copper mine site is located near Murdochville in Québec’s Gaspé Peninsula. The Company is currently focused on resource expansion of the Gaspé Copper deposits, with current pit-constrained Measured and Indicated Mineral Resources of 1.83 Bt averaging 0.32% CuEq and Inferred Mineral Resources of 239 Mt averaging 0.46% CuEq (in compliance with NI 43-101). For more information, see Osisko Metals’ April 14, 2026 news release entitled “Osisko Metals Announces Significant Increase in Mineral Resource at Gaspé Copper”. Gaspé Copper hosts the largest undeveloped copper resource in eastern North America, strategically located near existing infrastructure in the mining-friendly province of Québec.

In addition to the Gaspé Copper project, the Company is working with Appian Capital Advisory LLP through the Pine Point Mining Limited joint venture to advance one of Canada‘s largest past-producing zinc mining camps, the Pine Point project, located in the Northwest Territories. The current mineral resource estimate for the Pine Point project consists of Indicated Mineral Resources of 49.5 Mt averaging 5.52% ZnEq and Inferred Mineral Resources of 8.3 Mt averaging 5.64% ZnEq (in compliance with NI 43-101). For more information, see Osisko Metals‘ June 25, 2024 news release entitled “Osisko Metals releases Pine Point mineral resource estimate: 49.5 million tonnes of indicated resources at 5.52% ZnEq”. The Pine Point project is located on the south shore of Great Slave Lake, NWT, close to infrastructure, with paved road access, an electrical substation and 100 kilometres of viable haul roads.

For further information on this news release, visit www.osiskometals.com or contact:

Don Njegovan, President
Email: info@osiskometals.com
Phone: (416) 500-4129