Shares in Gem Diamonds Limited (LSE:GEMD, OTC:GMDMF)) fell 18% to 3.78p on Wednesday after the company reported a $104 million attributable loss for 2025, driven by a $77.5 million writedown of the carrying value of its Letšeng mine in Lesotho.
Revenue fell to $98.4 million from $154.2 million in 2025, while underlying EBITDA (earnings before interest, tax, depreciation and amortisation) collapsed to $3.9 million from $29.7 million.
The average value achieved per carat fell to $1,105 from $1,390, reflecting prolonged weakness in the rough diamond market and an unfavourable exchange rate between the US dollar and the Lesotho loti.
Net debt rose to $20.1 million from $7.3 million at the end of 2024.
The deteriorating results prompted Gem Diamonds to launch a Business Resilience Programme in the second half of 2025.
The company said renewing its group lending facilities, which expire in December 2026, remained a priority.
Chief executive Clifford Elphick said the measures taken had better positioned the group to benefit when market conditions improved.