Grab Holdings Ltd. ’s shares lost more than one-fifth of their value on their first day of trading in New York, a blow to the Southeast Asian ride-hailing and delivery giant after its record-breaking merger with a special-purpose acquisition company.

Shares fell 21% to $8.75, giving Grab a market capitalization of roughly $34.6 billion. The Singapore-based company in April agreed to combine with the SPAC Altimeter Growth Corp. in a deal that valued it at close to $40 billion, setting a high-water mark for transactions involving blank-check companies, which raise money with the purpose of seeking a target to merge with and take public.