Fund flows into Spac listings remain strong by historical standards. But signs of cooling have started to emerge. Shares in the Altimeter Spac rose a relatively modest 10 per cent on Tuesday, reflecting a decline in the last half-hour of trade. Gains of about 30 per cent were common following announcements of Spac deals last year. The benchmark Ipox Spac index is down a fifth since a February peak. Regulators have stepped up scrutiny.

Historically, the long-term performance of Spacs has been disappointing. Shares have traded substantially better pre-merger than post-merger, says Bain. Spacs have underperformed traditional listings by more than 50 percentage points in the past five years.