Over 41K contracts expired, over half of which were call options. This caused BTC to fall from 39.5K to 38.5K in minutes.

These options expired 1 day after BTC saw over 57K bitcoins leave exchanges.

“There is always additional activity before and just after the expiry, especially for relatively larger ones like the July expiry,” chief commercial officer at Deribit, Luuk Strijers, told CoinDesk.