ASX Biggest Losers Today: Austal, Metcash and Nanosonics Slide Even as the ASX 200 Surges (December 12, 2025)

Meta description: Australia’s sharemarket rallied on Friday, 12 December 2025, but several ASX shares sank sharply. Here are today’s biggest stock losers on the ASX, what’s behind the falls, and what analysts are watching next.

SYDNEY, December 12, 2025 — Australia’s sharemarket powered higher on Friday, with the S&P/ASX 200 up about 1.2% to around 8,692 in afternoon trade, helped by strength in materials and banks and a powerful run in gold-linked names. ^[1]

But even on a broadly green day, the “biggest losers” list still matters—because sharp declines often surface stock-specific catalysts (foreign investment rulings, trading halts, ex-dividend drops, sector rotations) that can reshape sentiment into year-end.

Below is a detailed look at the biggest ASX losers today (12.12.2025) —first among major large caps (including ASX 200 laggards), then across the broader market where percentage swings can be extreme.

Market backdrop: why the ASX rose while some shares still fell hard

By early afternoon, the market tone was decisively “risk-on” in Australia: materials surged to record highs and financials bounced strongly , pushing the benchmark towards a one-month high. ^[2]

At the same time, technology was the standout pocket of weakness , mirroring offshore moves after renewed debate about the profitability and payback of big AI spending plans—sparked by Oracle’s sharp fall and broader “AI capex” jitters. ^[3]

That split personality— resources and banks higher, tech softer —set up the day’s losers board: a mix of stock-specific headlines (Austal), mechanical ex-dividend effects (Metcash), and rotation pressure in growth/tech and select consumer names. ^[4]

Biggest ASX 200 fallers today (large caps)

By midday, MarketIndex’s large-cap tracking showed these names among the most notable decliners on the ASX 200 (moves reflect live pricing during the session). ^[5]

Large-cap losers (midday snapshot)

Metcash (MTS) : -3.12% to $3.26 ^[6]
Austal (ASB) : -3.04% to $6.23 (and later flagged down more sharply intraday) ^[7]
Eagers Automotive (APE) : -2.43% to $24.10 ^[8]
Genesis Energy (GNE) : -2.37% to $2.06 ^[9]
Lovisa (LOV) : -2.21% to $30.12 ^[10]
Technology One (TNE) : -1.77% to $27.16 ^[11]
Guzman y Gomez (GYG) : -1.57% to $21.26 ^[12]
Neuren Pharmaceuticals (NEU) : -1.43% to $19.31 ^[13]
Santos (STO) : -1.11% to $6.22 ^[14]
CAR Group (CAR) : -1.07% to $31.07 ^[15]

ABC’s afternoon snapshot similarly singled out Metcash as sitting at the bottom of the ASX 200 board at around -3.1% , underscoring how the selling remained concentrated even as the index rose. ^[16]

Why the biggest losers fell: today’s key headlines and drivers

1) Austal (ASB): stake decision sparks volatility after trading halt

Austal was among the day’s most closely watched decliners after it came out of a trading halt and fell. ABC reported the stock was down about 4.2% after the halt ended. ^[17]

The catalyst: Treasurer Jim Chalmers approved South Korea’s Hanwha to increase its Austal stake from 9.9% to 19.9% , but under strict conditions tied to governance and sensitive information access—reflecting the national security sensitivity around a strategic shipbuilder. ^[18]

Reuters detailed that Hanwha remains capped as a minority investor at 19.9% , with restrictions around data access and criteria for any board representation request. ^[19]
The Financial Times also highlighted the government’s emphasis on limiting influence due to defense sensitivities, while noting debate about potential operational benefits from Hanwha’s shipbuilding expertise. ^[20]

Market context: MarketIndex noted Austal had already had a blockbuster 2025 run and was trading at a technically significant level after pulling back from earlier highs. ^[21]

What to watch next (Austal outlook):

Whether Hanwha seeks board representation and how Austal responds (a key governance flashpoint). ^[22]
Any clarity from Austal on “partnership” requests or governance structures under the imposed conditions. ^[23]
Ongoing investor reassessment after a year of sharp gains and heightened defense-industrial scrutiny. ^[24]

2) Metcash (MTS): a classic ex-dividend drop, not necessarily “new bad news”

Metcash was a standout loser even as staples were not broadly collapsing.

The cleanest explanation is mechanical: Metcash’s investor center lists an interim dividend of $0.085 per share with an ex-dividend date of 12-12-25 (today), and a payable date of 28-01-26 . ^[25]

When a stock goes ex-dividend, it’s common to see the share price adjust lower by roughly the dividend amount (all else equal). In today’s trade, Metcash was down around 3% in the large-cap losers lists. ^[26]

What to watch next (Metcash outlook):

Whether the post ex-dividend adjustment stabilizes once income-focused buyers re-enter. ^[27]
Any updates on trading conditions in food, liquor, and hardware distribution into year-end. (Today’s move alone doesn’t prove deterioration; ex-dividend days can distort “losers” tables.) ^[28]

3) Tech and “growth” pressure: Technology One (TNE) and other laggards

While Australia’s market climbed on miners and banks, technology names were singled out as the main sector in the red —a pattern ABC described during the session. ^[29]

The global overlay mattered today. Reuters reported Asian markets were buoyed by Wall Street gains, but tech concerns raised after Oracle’s steep fall revived questions about AI investment returns. ^[30]

MarketIndex’s live commentary was blunt about the local picture too: several large-cap Aussie tech names have been in steep downtrends for months, making the sector vulnerable even on strong index days. ^[31]

What to watch next (tech outlook):

Whether offshore tech sentiment stabilizes after the Oracle/AI capex shock, or whether “profitability payback” remains the market’s focus. ^[32]
If the ASX rally broadens beyond materials/banks—because narrow leadership often leaves tech as a funding source. ^[33]

Biggest percentage stock losers across the broader ASX today

Beyond the ASX 200, the day’s biggest “percentage losers” were dominated by smaller resources and early-stage names—where liquidity is thinner and price moves can be exaggerated.

MarketIndex’s “Top Losers (percentage) today” scan showed the steepest falls including: ^[34]

Noronex (NRX) : -13.33% (turnover ~$23k) ^[35]
Heavy Minerals (HVY) : -12.93% (turnover ~$102k) ^[36]
Diablo Resources (DBO) : -12.50% (turnover ~$8k) ^[37]
Tasman Resources (TAS) : -12.50% (turnover ~$7k) ^[38]
Dundas Minerals (DUN) : -11.91% (turnover ~$3k) ^[39]
WIN Metals (WIN) : -11.91% (turnover ~$261k) ^[40]
Australis Oil & Gas (ATS) : -11.77% (turnover ~$60k) ^[41]
New Frontier Minerals (NFM) : -11.77% (turnover ~$22k) ^[42]
Australian Bond Exchange Holdings (ABE) : -11.11% (turnover ~$4k) ^[43]
Lion Rock Minerals (LRM) : -11.11% (turnover ~$181k) ^[44]

The most “liquid” notable fallers

Not every major loser was a tiny microcap. The same MarketIndex scan also flagged sharper declines in names with bigger market caps and/or meaningful turnover, including:

Nanosonics (NAN) : -6.68% (turnover ~$2.2m) ^[45]
Meteoric Resources (MEI) : -7.81% (turnover ~$1.35m) ^[46]
Marmota (MEU) : -7.69% (turnover ~$3.8m) ^[47]
Decidr AI Industries (DAI) : -7.76% (turnover ~$477k) ^[48]

In several of these cases, today’s drop appears to follow prior volatility. For example, Marmota had just attracted heavy attention after “bonanza” gold assay headlines earlier in the week, and sharp reversals after a spike are common in fast-moving small caps. ^[49]

Forecasts and analysis: what matters after today’s losers list

Today’s action investors leaves with three practical takeaways for the near-term outlook:

1) Leadership is narrowing—materials and banks are doing the heavy lifting

MarketIndex described one of the strongest sessions in months, led by Materials (+~1.7%) and Financials (+~1.5%) , while noting the benchmark was approaching key technical levels such as its 50‑day moving average . ^[50]

If that leadership continues, losers lists may keep featuring:

rate‑sensitive growth names,
consumer discretionary laggards,
and idiosyncratic “event” stocks (halts, regulatory rulings, capital actions).

2) Tech sentiment is being set offshore—AI spending scrutiny is back

Reuters coverage made clear why: Oracle’s earnings fallout reignited debate about AI capital spending and the speed of profits, feeding through to broader tech risk appetite. ^[51]

In practical terms: if global tech stabilizes, local tech may stop being the funding source for rotation; if not, local tech can keep appearing among “biggest losers” even on up days for the ASX.

3) “Biggest losers” doesn’t always mean “worst fundamentals”

Metcash is the best example today: ex-dividend mechanics can mechanically push a stock into the losers column without any fresh operational deterioration. ^[52]

Bottom line: today’s biggest ASX losers were driven by events, dividends and rotation—not a market-wide selloff

On 12 December 2025 , the ASX 200 rallied strongly, powered by miners, banks and gold-linked strength, but the biggest losers list still flashed meaningful signals:

Austal : policy and national‑interest constraints around a major shareholder’s stake increase drove volatility. ^[53]
Metcash : a dividend calendar event (ex-dividend day) likely explains much of the drop. ^[54]
Broader market : the largest percentage plunges were mostly in small caps—often where liquidity can amplify moves. ^[55]