South32 (ASX:S32) Hits 12-Month High After Manganese Surge: Time to Buy, Hold, or Take Profits?

South32 Surges on Strong Manganese Production

South32 (ASX: S32) jumped 5.2% to a fresh 12-month high of A$4.40 on Thursday after delivering a strong December quarterly update. The big story? Its Australian manganese ore operations have bounced back faster than expected from last year’s cyclone damage. But here’s the catch for investors thinking about buying now: the stock is trading well above where most analysts think it should be. So is this rally justified, or has the good news already been priced in?

What are the Best ASX Mining Stocks to invest in right now?

Check our buy/sell tips

Manganese Recovery Shows Management Can Execute

The real highlight of this quarter was the turnaround at South32’s manganese mines in the Northern Territory. Tropical Cyclone Megan caused major damage in March 2024, forcing the operation to essentially shut down. Fast forward to today, and production has not only recovered but exceeded expectations.

Here’s what that looks like in practice: in the entire 2025 financial year, Australia Manganese produced about 1.1 million wet metric tonnes (wmt) because of the cyclone disruption. In just the first half of FY26, production already hit 1.66 million tonnes. That’s a 50% increase in half the time, which tells us the recovery plan worked, and the operation is back to full strength.

Why does this matter for investors? Manganese is essential for steelmaking and batteries, and South32 is one of the world’s largest producers. Getting this operation back online means cash flow is returning to normal, which supports dividends and the company’s ongoing buyback program.

Mozal Shutdown and Stretched Valuation Raise Caution Flags

While the operational story is positive, we see two reasons for caution. First, South32’s Mozal aluminium smelter in Mozambique will shut down around mid-March 2026. The company spent years trying to negotiate affordable electricity prices but couldn’t reach a deal. This isn’t a small issue. Mozal accounted for nearly 30% of South32’s total aluminium production capacity last year, and closing it will cost around US$60 million in one-off expenses.

Second, and more importantly for anyone thinking of buying today, the valuation looks stretched. At A$4.40, South32 trades about 15-20% above where most analysts have set their price targets (around A$3.61-A$3.98). The stock has already run up 28% in just three months. In our view, that’s a lot of good news already baked into the share price.

The Investor’s Takeaway for S32

South32 remains a solid company with genuine strengths. It has pivoted towards metals that matter for the energy transition, including manganese, copper, and zinc. The balance sheet is healthy, and management has proven it can handle challenges like the cyclone recovery.

However, we believe much of this positive story is now reflected in the share price. For new investors, chasing the stock at 12-month highs feels risky when analysts see potential downside. We’d suggest waiting for a pullback towards the A$3.80-A$4.00 range for a better entry point.

For existing holders sitting on strong gains, this could be a sensible time to trim some profits. The Mozal shutdown will create near-term headwinds, and commodity prices remain unpredictable. South32 is a quality operator, but at current prices, patience looks like the smarter play.