3i Group shares nosedived up to 25% in European morning trading on Thursday, marking what would be the British private-equity firm's steepest single-day drop on record if sustained through market close. The dramatic sell-off reflects mounting investor concerns about the company's core holding.

The decline stems from disappointing performance at Action, the discount retailer representing the majority of 3i's portfolio value. Like-for-like sales growth slowed to 2.4% in the year to date, down sharply from 6.8% during the same period last year. Management attributed the weakness to deteriorating consumer sentiment across several markets, citing the Middle East conflict and unfavorable weather conditions as key headwinds.

Profitability metrics also deteriorated, with Action's operating EBITDA margin falling to 12.4% in the first quarter of 2026 compared to 14.8% for the full year 2025. This operational pressure compounds a brutal period for 3i shareholders, who have watched the stock lose more than half its value over the past twelve months.

The results highlight the vulnerability of private-equity firms concentrated in single holdings when consumer spending patterns shift unexpectedly. For 3i, the path forward depends heavily on stabilizing Action's performance amid ongoing macroeconomic uncertainty.