During the boom in blank-cheque companies, their creators couldn’t launch them fast enough. Now they are rushing to liquidate their creations before the end of the year, marking an ugly conclusion to the Spac frenzy.

With few prospects for deals soon and a surprise tax bill looming next year, special-purpose acquisition companies are closing at a rate of about four a day this month, nearly the same pace they were being launched when the sector peaked early last year.