Adam Savage's recent video said large companies don't like to lay off big blocks of employees so they just do it in small batches over the year. They fire the last person who made any mistake.
That doesn't fit my experience. Google's stock price increased after a large block of layoffs. And they were making every effort to put as many as possible in a single block. For example, my department was "impacted by the layoffs" but given 9 months to keep working and possibly transfer out. If they didn't want to announce a large number at once they easily could have waited.