Newsletter · · Ashutosh Agarwal

Copper Holds a 6 Dollar Floor and Chinas Sulfur Export Ban Threatens Phosphate Fertilizers - Industrial Materials - Week of May 26–29, 2026

Metals and materials weekly for May 26–29, 2026. A wall-to-wall copper tape converges on a $6+ structural-deficit thesis, while the under-priced read-through, China's sulfuric acid export ban, points straight at phosphate fertilizers.

Industrial Materials

Week of May 26–29, 2026: Copper Holds a 6 Dollar Floor and Chinas Sulfur Export Ban Threatens Phosphate Fertilizers

Hi,

Sometimes the most important trade of the week shows up sideways. This week's podcast tape was wall-to-wall copper, but the line worth circling came inside a copper episode and points straight at phosphate fertilizers. If you only have ten minutes today, read this for the sulfur story; the rest is supporting evidence.

TL;DR

  • Copper is now a $6+ commodity with operators calling it a floor, not a peak. Spot $6.30–$6.50/lb, COMEX-LME arb ~$500/mt, Grasberg offline until 2028, and a U.S. primary-copper tariff decision on the calendar.
  • The under-priced story is sulfuric acid. China banned sulfuric acid exports on May 1; ~50% of global sulfur transits Hormuz; sulfur prices +~80%. This hits ~17% of global copper supply (SX-EW, mostly DRC), and it is the dominant input cost for phosphate fertilizers. MOS and NTR phosphate exposure is the read-through nobody's talking about.
  • Rare earths, lithium, and U.S. steel were quiet on the pods this week. Aluminum got one mention (4-year high, China capacity throttle). I'd rather flag that than fabricate the missing legs.

What's New

1. The single most important episode of the week: Scott-Gray on the Hormuz/sulfur shock. On The Derivative ("'Dr. Copper': From Chilean Mines to Chinese Smelters to AI Data Centers," May 28), StoneX senior metals demand analyst Natalie Scott-Gray laid out the cleanest framing I've heard on copper this year. Two numbers to take away: she calls the U.S. refined-copper tariff deadline (July 30, with a proposed step-up to 15% by early 2027 and 30% by 2028) "arguably the most significant thing in the copper market that will happen this year"; and she flags China's May 1 ban on sulfuric acid exports as the supply shock the market hasn't priced. SX-EW is ~17% of global copper, ~60% of which sits in the DRC, with "2 to 3 months" of sulfur stocks. Co-host Kurt Nelson (SummerHaven, CPER ETF) added: "I haven't seen that flow through price yet."

2. Tariff arbitrage already happened, $1.6 million tonnes of it. Same episode: roughly 1.6 Mt of refined copper has already shipped to the U.S. on the CME-LME arb in the last year, with the spread peaking at "$3,000 premium, if not more." Q1 2026 global visible stocks (COMEX+LME+SHFE) hit a record, with the bulk in the U.S. Translation: a lot of the front-end of the tariff trade is in the price. The back-end, what happens to ex-U.S. inventories when the bonded copper stops flowing, is not.

3. Operator base case: $6 is a base, not a peak. On The KE Report ("Investors Rotating Money In Metals," May 28), Junior Stock Review's Brian Leni reported, from a direct conversation with an Australian concentrate trader, that smelter TC/RCs are persistently negative: "there's just no supply for these smelting operations. The negative treatment charges is here to stay." On Wall Street Unplugged (May 27), Coppernico CEO Ivan Bebek confirmed Grasberg "won't be able to go back into production until 2028" after the pit-wall collapse. He thinks "the price of copper is going to double in the next few years." When operators with skin in the game say "double from here," I don't dismiss it, but I do underwrite it.

4. The economics of new copper supply are still ugly, and that's the bull case. On Mining Stock Daily ("Live from the Deutsche Goldmesse," May 26), Marimaca CEO Hayden Locke benchmarked his $587M capex against peers: "the average capital cost two years ago was over $3 billion." Locke's AISC of ~$2.30/lb against a $6+ spot is the kind of margin that gets DFS projects financed; the problem is "the cupboards are very bare" of sub-billion-dollar capex projects. Greenfield lead time is now widely cited at 12–17 years.

5. Sell-side base-metals desk: floors have been reset. On The KE Report (Darrell Fletcher, May 27), Bannockburn's commodities MD pointed to LMEX +13% YTD, copper Dec-2028 contango at ~$7.00/lb, and aluminum at a 4-year high on China's capacity throttle (Midwest premium ~$1.15–$1.16/lb; LME aluminum >$3,600/mt). His read: "base-metal floors have really been reset."

The Debate

"By 2028, we hit a massive deficit in all sorts of critical minerals.", Tracy Shuchart, Mining Stock Daily, May 29

The bull case got the airtime this week. Six years of underinvestment, declining ore grades, AI/data-center demand layered on EV and grid, Grasberg out until 2028, Kamoa-Kakula flooding (output cut ~28% per Scott-Gray), and Chile earthquake disruption. Plus the resource-nationalism stack: Zimbabwe lithium ban, DRC cobalt restrictions, China's sulfuric acid ban. The structural-deficit thesis pegged to ~2030 was repeated, in some form, on every single episode this week.

The bear case, in fairness, was barely voiced on the pods this week. The honest pushback would be: record visible inventories in Q1, a meaningful chunk of the U.S. tariff trade already in the price, a hawkish Lisa Cook reminding everyone that the Fed cross-current is real (Mining Stock Daily morning briefing, May 28), and the awkward fact that nobody on the pod circuit this week made the demand-air-pocket argument with conviction. When the tape is this one-sided, that itself is a signal, usually that positioning is getting crowded.

The Names Actually Moved

  • FCX: Grasberg restart pushed to 2028 by multiple operator/CEO speakers. That's a real production hole.
  • TECK: Confirmed ~10% holder of Coppernico (per Bebek); Anglo merger forming the ~$80B base-metals co. Strategic signaling matters here.
  • MOS / NTR: Not mentioned by name on any episode this week, but the sulfuric acid input is the most under-discussed read-through in the tape. Do the work on phosphate cost curves before next week.
  • MARI (Marimaca): Fully permitted, DFS done, AISC ~$2.30/lb, FID mid-2027, a rare developer at sub-billion capex.

Read-Throughs

  • Copper royalties/streamers (FNV, WPM, RGLD, TFPM, OR): structural beneficiaries of any sustained re-rate, with no operational acid exposure. Nick Hodge (KE Report, May 29) noted the PICK ETF +~47% since October on a similar setup.
  • Phosphate (MOS, NTR phosphate, OCP): cost-curve read-through from sulfur +80% and the China acid ban is direct and underappreciated. Phosphate processing is acid-intensive.
  • Aluminum (AA, CENX): 4-year highs on China capacity discipline (45.5 Mt domestic ceiling) per Scott-Gray on The Derivative. Midwest premium structurally elevated.
  • Magnets / rare earths (MP, LYC, NEO): silent on the pods this week. With the April 2025 controls still in force and the one-year suspension running to November 2026, no operator voiced an updated view, which doesn't mean nothing is happening, it means we wait.

What Changed

The Hormuz/sulfur thread is the only genuinely new cross-asset story to surface this week. The structural copper deficit thesis is not new; what is new is that operators and analysts independently converged on it on the same week, at $6+ spot, with Grasberg's 2028 timeline now confirmed by a CEO with a strategic stake. The fertilizer angle is the second-derivative trade most people will miss because it broke inside a copper podcast.

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