Subscribers lost

Studio reports gains and losses separately, then nets them into the figure most people quote. The losses line covers anyone who unsubscribed, plus the accounts YouTube itself removed for spam or closure, which is why a channel can shed subscribers on a day it published nothing. Read the losses line against your publishing dates. The net number hides the churn underneath, and a spike in losses following one specific video says something about that video. A slow trickle is normal once a channel has some size to it.