Osisko Gold confirms mineralized system at Proserpine; drills 95.93 g/t Au over 4.60 m at Cariboo

TORONTO, Aug. 05, 2026 (GLOBE NEWSWIRE) -- Osisko Gold Group Inc. (NYSE: OGG, TSXV: OGG) (" Osisko Gold " or the " Company ") is pleased to announce its first set of new diamond drilling results consisting of fourteen holes from the surface exploration program on the Proserpine regional greenfield target, located within the broader Cariboo Gold Project property boundary and approximately 7 kilometres (" km ") from the Company's permitted, 100%-owned Cariboo Gold Project (the " Project ") in central British Columbia, Canada.

Chris Lodder, President, stated, " We are encouraged by the initial results from the drill campaign at Proserpine, which highlight the potential for a significant new gold mineralized system of scale located only 7 km from the Cariboo Gold deposit. Drilling has intersected high-grade structures showing similarities to those at Cariboo, but also containing areas with broader lower grade mineralization that may indicate potential for bulk mining methods. To date, drilling has broadly tested an area measuring approximately 1.0 km x 0.5 km within a larger target of 6.0 km x 1.0 km gold-in-soil and rock anomaly. For context, the currently defined Cariboo Gold deposit extends approximately 4.0 km along strike by 0.5 km in width, underscoring the exploration potential that remains to be tested at Proserpine."

DRILL ASSAY HIGHLIGHTS

This news release contains assays from fourteen (14) diamond drillholes (" DD ") totalling 6,463 meters (" m ") with depths ranging from 36.0 to 734.3 m ( see Table 1 and Figure 3 ) completed between February and May of 2026. All holes were collared in HQ (63.5 millimetre diameter) and reduced to NQ (47.6 millimetre diameter)