MOS Agriculture · Fertilizer · Commodities · Cyclical · Thesis updated July 12, 2026

Potash strength cannot cover phosphate pain

Q1 2026 sales rose, but Mosaic still posted a $257.6 million net loss as costs and Brazil charges hit earnings.
Sulfur costs rose 141% year over year in North America phosphate, crushing Phosphate gross margin to $3.4 million.
Potash is the bright spot, with Q1 2026 operating earnings of $177 million as prices and volumes improved.
Brazil is being reset after the Araxá divestiture plan and Patrocínio idling drove about $442 million of charges.
Finn's view is cautious because the best segment cannot fully offset weak margins, restructuring risk, and volatile Ma'aden gains.

01 Running thesis

A margin squeeze changed the story

Mosaic is still a key supplier of phosphate and potash crop nutrients. The long-term bull case rests on assets that are hard to copy: mines, processing plants, and distribution in North America and Brazil. Potash is carrying the company right now. In Q1 2026, Potash operating earnings rose to $177 million from $157 million a year earlier, helped by higher prices and volumes.

The problem is phosphate. Sulfur and ammonia are key inputs for phosphate fertilizer. In Q1 2026, North America sulfur costs rose 141% year over year, and Phosphate gross margin fell to $3.4 million from $167.3 million. Mosaic said higher raw material costs, mainly sulfur and ammonia, hurt gross margin by about $280 million.

Brazil added a second hit. Mosaic decided to divest the Araxá mining and chemical complex and idle related mining at Patrocínio. That led to about $442 million of charges and a $422 million operating loss in Mosaic Fertilizantes for Q1 2026.

The bull case needs three things to go right: sulfur and ammonia costs ease, Brazil becomes simpler and more profitable after the reset, and Mosaic finds a smart use for its Ma'aden shares. The bear case is more immediate. High input costs are already forcing phosphate production curtailments in the U.S. and Brazil, and that can keep earnings weak even if fertilizer prices look strong.

May 2026▼Q1 2026 changed the thesis for the worse. Sulfur costs rose 141% year over year, Phosphate gross margin fell to $3.4 million, and Brazil restructuring charges drove a large operating loss.

Feb 2026→The 2025 10-K kept the basic business and risk picture intact. Small non-core divestitures supported the portfolio clean-up story, but the filing did not change the core thesis.

Nov 2025▲Q3 2025 showed a rebound in Phosphate operating earnings and continued strength in Potash and Mosaic Fertilizantes. Ma'aden gains again showed that reported earnings can swing for non-operating reasons.

Aug 2025▼Q2 2025 introduced a new Phosphate headwind from environmental and asset retirement provisions. Potash and Brazil stayed strong, but the quality of earnings became less clean.

May 2025→Q1 2025 showed better Phosphate and Brazil results, but weaker Potash and a Ma'aden mark-to-market loss limited the improvement. The thesis became more mixed.

Mar 2025▲The Ma'aden transaction closed in December 2024 at about $1.5 billion, creating a possible source of future cash. The same update added tariff risk for Canadian potash and highlighted the growing Mosaic Biosciences platform.

02 Business model

Mines, plants, and farm demand

Mosaic makes money by mining phosphate rock and potash, turning those raw materials into concentrated crop nutrients, and selling them to wholesalers, retailers, and farm cooperatives. Farmers use these products to improve crop yields. Demand follows crop economics, planted acres, and fertilizer affordability.

The model is capital heavy. Mines and processing plants cost a lot to build, permit, and run. That gives Mosaic a barrier to entry, since few new rivals can quickly create similar mining assets. It also means fixed costs matter. When plants are curtailed, fewer tonnes carry the same fixed cost base.

The biggest break point today is input cost. Phosphate needs sulfur and ammonia, and those inputs became much more expensive in Q1 2026. Potash has a cleaner cost story right now, but it has its own risks, including Canadian taxes, mine issues, global demand swings, and possible U.S. tariffs on Canadian potash.

03 Product portfolio

What Mosaic sells

Steady

DAP and MAP phosphate fertilizers

These are core phosphate products used by farmers around the world. They can earn good money when prices are firm, but Q1 2026 showed how sulfur and ammonia costs can wipe out the benefit.

Option

MicroEssentials

MicroEssentials is Mosaic's value-added phosphate product. It is part of the Phosphate segment's performance and other category, alongside animal feed ingredients.

Cash cow

Muriate of potash

MOP is Mosaic's main potash product. Potash is currently the company's strongest segment, with Q1 2026 operating earnings rising to $177 million.

Steady

K-Mag and Aspire

These are potash-based specialty products. They add mix and product choice beyond standard MOP.

Steady

Mosaic Fertilizantes

This segment serves Brazil by producing and distributing phosphate and potash fertilizers, plus third-party nutrients. It is under pressure after the Araxá divestiture plan and Patrocínio idling.

Option

Mosaic Biosciences

This platform sells biological fertilizer complements that help plants use nutrients better. It doubled its acres of coverage in 2024, but it is still small next to phosphate and potash.

04 Business segments

Q1 2026 segment mix

Phosphates47%declining

Potash22%modest

Mosaic Fertilizantes31%declining

Shares use Q1 2026 operating segment net sales: Phosphate $1.426 billion, Potash $667.4 million, and Mosaic Fertilizantes $937.1 million. This mix excludes Corporate, Eliminations and Other, so it is a segment view rather than consolidated net sales.

05 Risk factors

What could break the thesis

Sulfur and ammonia stay expensive

High impact · High odds

Phosphate profits are very sensitive to sulfur and ammonia. In Q1 2026, higher raw material costs, mainly sulfur and ammonia, hurt Phosphate gross margin by about $280 million. If the Middle East shipping and supply issues persist, the Phosphate segment could stay near break-even or worse.

We watchNorth America sulfur cost per long ton, ammonia cost per tonne, and Phosphate gross margin each quarter.

Production curtailments drag on

High impact · Medium odds

Mosaic is partially curtailing production at Louisiana and Bartow, Florida, and scaling back in Brazil. Curtailments protect cash when margins are poor, but they can also hurt fixed cost absorption. If plants stay below normal rates, reported margins may lag even after selling prices improve.

We watchManagement updates on Louisiana, Bartow, and Brazil operating rates, plus any restart conditions.

Brazil restructuring costs more than planned

High impact · Medium odds

The Araxá divestiture plan and Patrocínio mine idling caused about $442 million of Q1 2026 charges. The bull case says Brazil becomes cleaner and more profitable after the reset. The risk is that sale value disappoints or more charges appear.

We watchAraxá sale price, closing timing, added impairment charges, and any savings targets for Mosaic Fertilizantes.

Potash loses its safe-haven role

Medium impact · Medium odds

Potash is the strongest current segment, but it is still a commodity business. Prices can fall if global supply improves or farmers delay buying. Possible U.S. tariffs on Canadian potash could also reduce U.S. demand or shift trade flows.

We watchMOP selling price, Potash sales tonnes, Canpotex export trends, and U.S. tariff actions on Canadian potash.

Ma'aden shares cloud reported earnings

Medium impact · High odds

Mosaic's Ma'aden stake can create large non-operating gains or losses. Q1 2026 included an unrealized mark-to-market gain of about $112 million, while Q1 2025 included a loss of about $120 million. That can make net income look better or worse than the core fertilizer business.

We watchQuarterly Ma'aden mark-to-market gain or loss and any plan to sell or hedge the stake.

06 Quick answers

In one breath

What does The Mosaic Company do?

Mosaic produces and markets phosphate and potash fertilizers. These nutrients help farmers grow crops, and Mosaic sells them through agricultural wholesalers, retailers, and cooperatives.

Why did Mosaic lose money in Q1 2026?

The main causes were high input costs and Brazil restructuring charges. Phosphate margins were crushed by sulfur and ammonia inflation, while the Araxá and Patrocínio actions drove about $442 million of charges.

What is the most important metric to watch for MOS?

Watch Phosphate gross margin and the cost of sulfur and ammonia. If those input costs fall, the earnings picture can improve quickly. If they stay high, production curtailments may last longer.

Is potash enough to fix Mosaic's problems?

Not by itself. Potash is performing well, with Q1 2026 operating earnings of $177 million, but Phosphate and Mosaic Fertilizantes were both loss-making in the same quarter.