<img src="https://ml.globenewswire.com/Resource/Download/88fd0127-8855-4e86-848e-6a036363adfb?size=2" nborder="0" align="left" hspace="5" vspace="5" title="Zac Logo - Updated.jpg" alt="Zacatecas Silver Corp."/>VANCOUVER, British Columbia, June 09, 2026 (GLOBE NEWSWIRE) -- Zacatecas Silver Corp. (“Zacatecas Silver” or the “Company”) is pleased to announce the assay results from the initial rock-chip sampling program at the Oso Negro project, located in Sonora, Mexico. The program was completed in March 2026 and samples were assayed by ALS (see Company News Release April 16, 2026). Highlights of the Sampling Program: <ul type="disc"><li style="margin-bottom:8pt;">Up to 14.8 g/t Au and 2,340 g/t Ag returned from surface rock-chip sampling at Oso Negro, Sonora </li><li style="margin-bottom:8pt;">39 of 134 vein samples assayed above 1 g/t Au; 35 samples above 100 g/t Ag, with strong correlation between gold, silver, lead, and zinc across the vein system </li><li style="margin-bottom:8pt;">High-grade results confirmed across a minimum 2 km combined strike length on two veins, demonstrating system-scale continuity </li><li style="margin-bottom:8pt;">Samples were collected above the boiling zone where grades are expected to be lowest in a low sulphidation epithermal system - indicating the highest-grade portion of the system remains untested at depth </li><li style="margin-bottom:8pt;">Three outcropping low sulphidation veins identified, up to 3 m wide, multiphase and brecciated, consistent with a well-developed epithermal system </li></ul> One hundred and fifty-six rock-chip grab samples were collected from three outcropping low sulphidation veins with a cumulative strike length of over 2 km. Of these, 134 samples were collected directly from vein outcrop; the remaining 22 were orientation samples collected from host rocks distal to the veins. Veins are up to 3 m wide, multiphase, with common vein breccias and pervasive iron oxides after sulphides. Of the 134 vein samples, 39 assayed between 1 g/t Au and 14.8 g/t Au, 35 assayed between 100 g/t Ag and 2,340 g/t Ag, and 11 assayed over 1% combined lead and zinc. Gold, silver, lead, and zinc show strong positive correlation throughout the sample population. High-grade results were returned across the full strike length of the Prospecto Vein and over approximately 1 km of the Tere Vein. The significance of these results is amplified by three geological factors. First, quartz vein textures and mineralogy confirm that samples were collected from the uppermost levels of the low sulphidation system - above the boiling zone where precious metal deposition is concentrated. Second, many samples were partially oxidized and leached at surface, conditions that typically suppress assay values relative to fresher material at depth. Third, despite these factors, anomalous gold and silver grades were returned consistently across the full 2 km strike length of the system. Taken together, the results indicate that the highest-grade portion of the Oso Negro system remains intact and untested below the current sampling interval. Vein textures are typical of the uppermost levels of a low sulphidation epithermal system. Where the boiling zone is preserved at depth, precious metal mineralization is expected to be present. The Company considers Oso Negro a compelling drill target. The Company is advancing Oso Negro on an accelerated timeline. High-resolution multispectral satellite imagery has been commissioned to provide a structural and alteration base map, which will guide an extensive follow-up rock-chip and channel sampling program to be conducted concurrently. The Company intends to submit a drill permit application to SEMARNAT before the end of June 2026. <img alt="Picture1" height="582" name="GNW_RichHtml_IMG" src="https://ml.globenewswire.com/Resource/Download/72aa7704-2553-4762-b72b-125c8772afcf/picture1.png" width="600" data-dpi="144" data-caption="Map of outcropping veins at Oso Negro showing location of rock chip samples: black dot sample less than 1 g/t Au, yellow dot 1-5 g/t Au, and red dot &gt;5 g/t Au." data-filename="Picture1.png" /> Figure 1: Map of outcropping veins at Oso Negro showing location of rock chip samples: black dot sample &lt;1 g/t Au, yellow dot 1-5 g/t Au, and red dot &gt;5 g/t Au. <img alt="Picture2" height="566" name="GNW_RichHtml_IMG" src="https://ml.globenewswire.com/Resource/Download/39b78d03-ec63-4638-9921-d0f3fd9245bb/picture2.png" width="600" data-dpi="144" data-caption="Map of outcropping veins at Oso Negro showing location of rock chip samples: black dot sample less than 100 g/t Ag, grey dot 100-500 g/t Ag, cyan dot 500-1000 g/t Ag and blue dot &gt; 1000 g/t Ag." data-filename="Picture2.png" /> Figure 2: Map of outcropping veins at Oso Negro showing location of rock chip samples: black dot sample &lt;100 g/t Ag, grey dot 100-500 g/t Ag, cyan dot 500-1000 g/t Ag and blue dot &gt;1000 g/t Ag. Analytical Methods and QA/QC Rock chip samples were collected and bagged under the supervision of Company personnel following standard industry practices. Samples were submitted to ALS Zacatecas for analysis. Samples were prepared by drying, sieving and pulverizing, and analyzed for Ag and a suite of elements by multi-element ICP methods following four-acid digestion. The Company inserted certified reference materials, blanks and field duplicates into the sample stream to monitor analytical quality. About Zacatecas Silver Corp. Zacatecas Silver is a multi-asset precious metals exploration company with a portfolio of six projects across Mexico, spanning Zacatecas, Sonora, Morelos, and Oaxaca. The Zacatecas Silver Project is located in Zacatecas State, within the highly prospective Fresnillo silver belt, which has produced over 6.2 billion ounces of silver. The Company holds 7,826 hectares of ground prospective for low-sulphidation and intermediate-sulphidation silver-base metal mineralization. A Mineral Resource Estimate at the Panuco deposit comprises 3.41 million tonnes at 187 g/t AgEq for 20.5 million ounces AgEq (see news release dated May 31, 2023). The property is 25 km southeast of MAG Silver's Juanicipio Mine and Fresnillo PLC's Fresnillo Mine, and shares boundaries with Defiance Silver and Endeavour Silver. The Esperanza Gold Project is located in Morelos State and hosts a Mineral Resource Estimate of 30.5 million tonnes at 0.97 g/t AuEq for 956 thousand ounces AuEq (Measured and Indicated) and 8.7 million tonnes at 0.98 g/t AuEq for 277 thousand ounces AuEq (Inferred) (see news release dated November 16, 2022). The Company also holds four exploration properties in Sonora and Oaxaca. Oso Negro (Sonora) is an undrilled, high-grade low sulphidation epithermal system with multiple veins across a 2 km strike length. Cumaro (Sonora) is situated along trend from Coeur Mining's El Picacho development and hosts extensions of proven low sulphidation vein systems with high-grade channel sampling results. La Lola (Sonora) is a large, underexplored 1,183-hectare property anchored by the La Barra vein, a 5 km structure reaching up to 40 m in width. Ejutla (Oaxaca) comprises 10,603 hectares in the Taviche-Miahuatlán region near the former Fortuna Silver San José Mine, hosting multiple vein systems and alteration zones anomalous in gold, silver, and Carlin-style pathfinder elements. Qualified Person The technical information in this news release has been reviewed and approved by Chris Wilson, B.Sc. (Hons), PhD, FAusIMM (CP), FSEG, FGS, Chief Geologist of Zacatecas Silver. Dr. Wilson is a Qualified Person as defined by NI 43-101 and is not independent due being Chief Geologist and a director. On behalf of the Company Eric Vanderleeuw Chief Executive Officer and Director (519) 729 2440 Forward-Looking Statements Information set forth in this news release contains forward-looking statements that are based on assumptions as of the date of this news release. These statements reflect management’s current estimates, beliefs, intentions and expectations. They are not guarantees of future performance. Zacatecas Silver cautions that all forward-looking statements are inherently uncertain and that actual performance may be affected by many material factors, many of which are beyond their respective control. Such factors include, among other things: risks and uncertainties relating to Zacatecas Silver’s limited operating history, its proposed exploration and development activities on is Zacatecas Properties and the need to comply with environmental and governmental regulations. Accordingly, actual and future events, conditions and results may differ materially from the estimates, beliefs, intentions and expectations expressed or implied in the forward-looking information. Except as required under applicable securities legislation, Zacatecas Silver does not undertake to publicly update or revise forward-looking information. Neither TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the Exchange) accepts responsibility for the adequacy or accuracy of this release. 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Zacatecas Silver Reports High-Grade Gold and Silver Surface Sampling Over 2 km Strike Length at Oso Negro, Sonora

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