The S&P/ASX 200 Index (ASX: XJO) is in course to record a small decline. In afternoon trade, the benchmark index is down 0.25% to 8,675.7 points.
Four ASX shares that are falling more than most today are listed below. Here's why they are tumbling:
Boss Energy Ltd (ASX: BOE)
The Boss Energy share price is down a further 7% to $1.77. Investors have been selling this uranium producer's shares this week after it released its fourth quarter update. While the company performed positively during the quarter, its guidance for FY 2026 disappointed the market. Management advised that in FY 2026 its Honeymoon Project is targeting production of 1.6Mlbs U3O8 with a C1 cash cost of A$41 to A$45/lb (US$27-29/lb). This was well short of expectations, sparking a significant selloff. This morning, Morgan Stanley responded to the update by retaining its underweight rating and cutting its price target to $1.65 (from $3.25).
DroneShield Ltd (ASX: DRO)
The DroneShield share price is down 5% to $2.84. This appears to have been driven by more profit taking after some strong gains in 2025. In addition, news that US President Donald Trump has brought forward its deadline for the end of the Russia-Ukraine war could be weighing on sentiment. Some investors may believe this could lead to softening demand for DroneShield's counter drone technology products in the region.
Greatland Resources Ltd (ASX: GGP)
The Greatland Resources share price is down 21% to $5.45. Investors have been selling this gold and copper miner's shares following the release of its quarterly update. Greatland revealed that its quarterly production was 78,283oz of gold and 3,729t of copper at an all-in sustaining cost (AISC) of $1,736 per ounce. With a weighted average realised price of $5,014 per ounce, the miner generated revenue of $487 million for the period. However, investors may be disappointed with its guidance for FY 2026. It expects an AISC of $2,400 to $2,800 per ounce.
Viva Energy Group Ltd (ASX: VEA)
The Viva Energy share price is down 10% to $1.97. This follows the release of a trading update from the fuel and convenience retailer this morning. Viva Energy revealed that it expects to report first half group EBITDA (replacement cost) of $300 million. This is down from $452 million in the prior corresponding period. Management advised that convenience sales were down 10% compared with the same period last year. This was driven by a decline in tobacco sales.
