ANTOFAGASTA PLC (ANTO) — Investment Research Note

Executive summary

Antofagasta is a Chile-focused, majority Luksic-family-controlled pure-play copper producer operating four mines (Los Pelambres 60%, Centinela 70%, Antucoya 70%, Zaldívar 50% JV) with a substantial multi-year growth pipeline led by the Centinela Second Concentrator (+170kt Cu-eq p.a.). Across the period covered the business has swung from peak 2021 earnings (EPS 142.5¢), through a mid-cycle 2022-24 phase where drought, pipeline disruptions, grade decline and inflation compressed unit economics, and back into a strongly rising phase in H1 2025 (EBITDA +60% YoY, 58.8% margin, underlying EPS doubled to 47.4¢) as concentrator/desalination projects ramp up and by-product prices boost credits. The most important point for valuation today is that the shares have re-rated ~90% in the past 12 months on a copper-price/AI-electrification narrative, leaving the stock priced on demanding EV/EBITDA multiples that already embed the growth pipeline and elevated copper prices.

Fair value estimate

• Fair value range: 2,600p – 3,300p per share (implied market cap £2,560m – £3,250m → £25,600m – £32,500m in GBP millions)
• Methodology: Blended EV/EBITDA multiple on attributable EBITDA at a mid-cycle copper price of $4.00–$4.30/lb, cross-checked against a simplified DCF/NAV using the company's own long-term copper price assumption of $4.50/lb (real 2025) from its Zaldívar and Buenaventura impairment models 2025-08 HY, Notes 4 & 13.
• Key assumptions:
  • 2025 attributable Cu production ~470kt (60/70/70/50% of ~680kt gross), rising toward ~590kt attributable in medium term post-Centinela Second Concentrator (+170kt gross, ~120kt attributable) 2024-02 FY.
  • Attributable EBITDA (mid-cycle) $2.8–$3.5bn; H1 2025 group EBITDA of $2,234m annualises to ~$4.5bn but includes elevated realised prices (Cu $4.55/lb realised vs LME $4.28/lb H1 2025) 2025-08 HY.
  • EV/EBITDA multiple range 7.5x–9.5x — in line with global pure-play copper peers (Freeport, First Quantum, Southern Copper), giving no growth premium at low end and modest premium at high end.
  • Net debt attributable $1,575m at 30 Jun 2025 2025-08 HY.
• Comparison to current market cap of £39,247m: Mid-point fair value £29,050m → downside of ~26% (per-share midpoint 2,950p vs 4,029p spot).
• Absolute up/down: -26% to -18% at fair value range extremes; +9% to +19% at highest end of range if a strong copper cycle is assumed to persist through 2027.

Sector context

• Sector confirmed: Basic Materials / Basic Resources — Diversified Mining (Copper pure-play).
• Quality/growth profile vs peers: above sector average on quality (net debt/EBITDA 0.54x, top-quartile EBITDA margin ~59% for pure-play copper H1 2025 2025-08 HY), above average on growth (medium-term +30% Cu output guided), below average on jurisdictional risk (single-country Chile exposure, new mining royalty regime effective 2024).
• Listed peers: Freeport-McMoRan (FCX), Southern Copper (SCCO), First Quantum Minerals (FM.TO), KGHM, Anglo American (partial).

Investment thesis

1. Best-in-class copper margins with visible ~30% volume growth from a funded, permitted pipeline — H1 2025 EBITDA margin 58.8% and net cash costs of $1.32/lb are at the top end of global pure-play peers, and the Centinela Second Concentrator (33% complete, $1.9bn spent) is on schedule for 2027 first production with a ~170kt copper-equivalent boost that will lower district cash costs toward the first quartile 2025-08 HY; 2024-02 FY.
2. Structural copper supply-demand tightness underpinned by electrification, data-centre buildout and grid capex — Management cites AI, decarbonisation and infrastructure as key demand drivers; Wood Mackenzie estimates need for +790ktpa of new copper approvals to balance the market by 2034 2024-02 FY. Antofagasta owns a 21bt Mineral Resource base concentrated in stable Chilean assets.
3. Fortress balance sheet enables self-funded growth and a policy-driven 35%+ payout — Cash & liquid investments of $4.58bn against $6.87bn borrowings (net debt 0.54x EBITDA), a $500m undrawn RCF, 94% of borrowings maturing after one year, and a track record of 35% payout on H1 (with excess cash returned via final dividends) provides genuine downside protection 2025-08 HY.

Key risks

1. Copper price cyclicality and current price is materially above long-run consensus — A 10% move in copper equals ~$306m of H1 2025 EBITDA impact; the price has run from ~$3.55/lb (2023 trough) to $4.55/lb realised in H1 2025, so mean reversion of even 15-20% would remove ~$800m-1,000m of annual EBITDA 2025-08 HY.
2. Chilean political, regulatory and water-scarcity risk — The new mining royalty regime took effect 2024 (Los Pelambres already impacted; Centinela/Antucoya from 2030 when tax stability agreements expire); Zaldívar's mine-life extension EIA is still under review, and Los Pelambres has faced repeated drought-related throughput cuts (2022 pipeline incident, 2023 water restrictions) 2025-08 HY; 2024-08 HY; 2023-02 FY.
3. Capital expenditure inflation on a $3.9bn 2025 capex programme — Centinela Second Concentrator was re-estimated up from $2.7bn (2015 pre-FS) to $4.4bn (2023), and Los Pelambres Phase 1 rose from $1.7bn to $2.3bn largely on COVID, inflation and Chilean peso — leaving material overrun risk on the remaining $3-4bn of growth capex through 2027 2024-02 FY; 2022-08 HY.

Operating leverage

Antofagasta has classic asset-heavy commodity operating leverage but not the software/platform style leverage the reader is targeting. The fixed-cost base is high: H1 2025 depreciation alone was $858m and sustaining/mine-development capex ~$856m, against a mine-site cash cost base of ~$1.6bn. Because copper revenue is essentially price × volume with cash costs largely determined by ore grade, throughput and input prices (diesel, acid, electricity, labour), incremental revenue from a copper price rise drops through at very high contribution margin — the H1 2025 disclosure quantifies this as $306m of EBITDA per 10% Cu price move on H1 revenues 2025-08 HY sensitivities. At the current attributable production of ~470kt, a 10-20% volume surprise (e.g. faster Centinela Second Concentrator ramp) would add ~$400-900m EBITDA at mid-cycle margins. The bigger inflection is post-2027 when Centinela's second concentrator reaches nameplate: management guides Centinela district cash costs into the first quartile, which would compound margin expansion on top of volume growth. However, in a downcycle the same leverage runs the other way — at $3.00/lb copper, group EBITDA would fall by roughly $2.4bn versus H1 2025 annualised. Contribution margins on incremental copper are high (~70%+ at current prices), but this is not "capital-light scale economics"; it is capacity-constrained, capital-heavy commodity leverage. 2025-08 HY; 2024-02 FY.

Value-trap signals

• None identified as classic value-trap signals — the business is profitable, cash-generative, dividend-paying, and growing production. Notable but manageable observations:
  • Rising net debt (was net cash $540m at end-2021; net debt $2.29bn H1 2025) as growth capex outpaces operating cash flow at current dividend policy — trajectory to watch.
  • Related-party transactions with Luksic-controlled entities (ENEX fuel, Banco de Chile, Compañía de Inversiones Adriático, Antomin exploration properties) — routine, disclosed and independently approved, but consistent feature of the ownership structure.
  • Twin Metals Minnesota project fully impaired ($178m in 2021) after US federal actions; ongoing litigation with uncertain outcome.

Earnings vs. expectations

Across the period covered, delivery vs guidance has been mixed with a lean toward misses in 2022-23 and beats in H1 2025:

• 2021 (FY): Copper production 721.5kt vs original guidance 730-760kt — modest miss due to drought.
• 2022 (H1 update): Production guidance cut from 660-690kt to 640-660kt after Los Pelambres pipeline incident and drought — guidance cut mid-year 2022-08 HY.
• 2023 (H1 update): Guidance cut from 670-710kt to 640-670kt on desalination delays and water shortage — second consecutive year of guidance cut 2023-08 HY.
• 2024 (FY): Production 664kt, at the lower half of 670-710kt guidance range — modest miss.
• H1 2025: Cu 314.9kt (+11%), cash costs 12% lower, EBITDA +60% — material beat on cost delivery, and FY guidance maintained at 660-700kt.

Pattern: management has repeatedly under-delivered on production guidance during weather- and project-disruption years (2022-24), but 2025 shows a return to positive operating momentum. Consensus references are limited in the filings.

Conviction

Conviction: 4 (High) — I am confident the stock is currently overvalued to fairly valued at the top end of my range.

Anchoring the conviction:

• Very clean, well-audited IFRS disclosure with a decade of comparable production, cost and pricing data; unqualified auditor opinions throughout.
• Business model is transparent (four operating mines, one commodity, well-quantified sensitivities).
• Multiple valuation approaches (EV/EBITDA at various cycle prices, attributable NAV, peer comparison) all converge in the £26-32bn range vs the current £39bn.

Limiting the conviction:

• Copper price is the dominant driver and structurally hard to forecast — a persistent super-cycle scenario (>$5/lb sustained) would validate the current price.
• The Centinela Second Concentrator delivery and ramp is the single most important operational catalyst and could de-risk faster than expected.