I think the post established that this volume or size of spike is unique before any market-shifting news event coming out of the government in recent decades. The "sort" of transaction is irrelevant except that it's risky and thus relatively low volume normally.
I said it happens in individual stock cases, but very few people / places that control major market moving news leak - and when they do they investigate the hell out of it.
Imagine if this happened 20 minutes before Jerome Powell unexpectedly dropped interest rates?
I think the post established that this volume or size of spike is unique before any market-shifting news event coming out of the government in recent decades. The "sort" of transaction is irrelevant except that it's risky and thus relatively low volume normally.