SCHEDULE: GMT Capital Discloses 6.28% Stake in ERO Copper Corp.

GMT Capital Corp. and Thomas E. Claugus have reported a 6.28% beneficial ownership stake in ERO Copper Corp. as of September 30, 2025.

Summary

• GMT Capital Corp. and its control person, Thomas E. Claugus, collectively beneficially own 6,509,454 shares of ERO Copper Corp. Common Stock.
• This ownership represents 6.28% of ERO Copper Corp.'s outstanding common stock.
• The percentage is calculated based on 103,607,249 shares outstanding as of August 28, 2025, as reported in the issuer's Short Form Base Shelf Prospectus.
• Both reporting persons hold shared voting and shared dispositive power over all 6,509,454 shares.
• The shares are held through various managed funds and accounts, including Bay Resource Partners, L.P., Bay II Resource Partners, L.P., Bay Resource Partners Offshore Master Fund, L.P., and other sub-advisory and separate account clients advised by GMT Capital.
• The acquisition of these securities was made in the ordinary course of business and not for the purpose of changing or influencing the control of ERO Copper Corp.

Sentiment

Score: 5

Explanation: The filing is a routine disclosure of beneficial ownership by an institutional investor, indicating a neutral sentiment as it does not contain performance data, strategic updates, or explicit positive/negative news about the issuer.

Positives

• Not applicable to this type of filing, which primarily discloses beneficial ownership.

Negatives

• Not applicable to this type of filing, which primarily discloses beneficial ownership.

Risks

• Not applicable to this type of filing, which primarily discloses beneficial ownership and does not detail issuer-specific risks.

Future Outlook

Not applicable to this type of filing, which primarily discloses beneficial ownership and does not provide forward-looking statements or guidance from the issuer.

Management Comments

• GMT Capital Corp. and Thomas E. Claugus certified that the securities were acquired and are held in the ordinary course of business and not for the purpose or with the effect of changing or influencing the control of ERO Copper Corp.

Industry Context

This filing is a routine disclosure of a significant ownership stake by an institutional investor in a publicly traded copper mining company. It does not provide specific industry analysis or relate to broader industry trends beyond the fact that a major investment firm holds a position in a company within the sector.

Stakeholder Impact

• Shareholders: Disclosure of a significant institutional holding can provide transparency regarding the ownership structure and potentially influence investor confidence or market perception of ERO Copper Corp.

Key Dates

Keywords

ERO Copper Corp, GMT Capital Corp, Thomas E. Claugus, Beneficial Ownership, Schedule 13G, Common Stock, Investment Adviser, Copper Mining