Sierra Metals Inc. has filed a technical report prepared in accordance with National Instrument 43-101 (“NI 43-101”) on the Yauricocha Mine (the “Report“). The Report supports the disclosure made by the Company in its news release dated November 18, 2020 entitled “Sierra Metals Announces Large Increase in Mineral Resource Tonnage at its Yauricocha Mine in Peru and Positive Preliminary Economic Assessment for Increase in throughput to 5,500 Tonnes Per Day from Today’s permitted 3,150 Tonnes Per Day.” This Mineral Resource Update and Preliminary Economic Assessment (“PEA”) report was prepared as a National Instrument 43-101 Technical Report for Sierra Metals Inc. (“Sierra Metals”) by SRK Consulting (Canada) Inc. (“SRK”) and Sierra Metals. There are several important differences in the PEA results contained in the Report from those disclosed in the November 18, 2020 news release as a result of adjustments and refinements in underlying calculations and estimates that feed into the model on which the PEA is based. These are included in the summary highlights below. After-tax Net Present Value (NPV): USD 359 Million(previously USD 333 Million) at an 8% discount rate. Plant Processing Rate after expansion: 5,500 tonnes per day (TPD) Incremental benefit of increasing the production to 5,500 TPD from 3,780 TPD is estimated to have an after-tax NPV (@8%) of USD 28.4 Million(previously USD 27.1 Million), and an IRR of 35.7% (previously 29.5%). Net After-tax Cash Flow: USD 527 Million(previously USD 495 Million). Life of Mine & Sustaining Capital Cost: USD 234.9 Million(previously USD 268.5 Million). Total Operating Unit Cost: USD 42.25/tonne (previously USD 48.89/tonne) and USD 1.19/lb (previously USD 1.28/lb) copper equivalent. Average LOM Grades of Silver 34.2 g/t (1.1 oz/t), Copper 1.28%, Gold 0.42 g/t (0.01 oz/t), Zinc 1.71% and Lead 0.48%. Copper Price Assumption USD 3.05/lb. MineLife: 12 years based on updated Mineral Resource Estimate which includes a 26% increase in the Measured and Indicated Resource category and a 79% increase in the Inferred Resource category. Life of Mine Payable Production: Copper 424 million pounds (previously 419 million pounds), Silver 13.1 million troy ounces (previously 13.7 million troy ounces), Gold 41.6 thousand troy ounces (previously 43 thousand troy ounces), Zinc 549 million pounds (previously 541 million pounds), Lead 169 million pounds (previously 167 million pounds). 3,780 tonnes per day represents the expected upcoming expansion to 3,600 tonnes per day plus a 5% overallotment allowance. Sierra is awaiting this permit from the government and expects to receive it in first quarter 2021. The Report dated November 19, 2020 with an effective date of June 30, 2020 is entitled “Preliminary Economic Assessment, Yauricocha Mine, Yauyos Province, Peru” and was prepared by SRK Consulting (Canada) Inc. and Sierra Metals Inc.