I read on https://www.kiplinger.com/investing/stocks/601168/spacs-to-buy:
Generally, the SPAC (Special-purpose acquisition company) will offer at $10 per "unit." Each unit includes one share of common stock and one-fourth of one warrant, which entitles the holder of one redeemable warrant to buy a share at, say, $11.50, or some other higher price determined by the sponsors.
Why do SPAC units typically start trading at 10 USD?