My understanding of the ETF transmission chain is roughly like this, using Friday as an example ETF holders sell IBIT in the secondary market after opening ->Secondary market IBIT negative premium (compared to actual net worth) ->AP (a large investment bank that actually has the authority to subscribe and redeem IBIT) sees arbitrage opportunities and buys cheap IBIT from the secondary market, while selling BTC in their inventory to hedge delta (this is the transmission chain from ETF secondary market sales to actual BTC selling pressure) ->On Friday, AP approached BlackRock to apply for the redemption of IBIT (using the IBIT purchased from the secondary market on Friday to retrieve BTC from BlackRock) ->BlackRock reports net outflow for the day after hours (AP redemption operations) ->T+1 means delivery on Monday. BlackRock will retrieve the funds from AP and return them to IBIT for destruction, while also transferring BTC to AP (as seen today). AP received BTC to fill the previous BTC inventory. I should have received more than what I sold during yesterday's hedge because IBIT was hit by a negative premium in the secondary market during the hedge. When AP redeems, they receive BTC based on their net worth. This becomes the source of AP profits. ------------ BlackRock has always been a custodian of BTC, with AP exchanging BTC for IBIT (subscription). Or using IBIT to exchange for BTC (redemption), the real dynamic trader of BTC is AP. ------------ The same applies to net inflows (subscriptions). Someone buys ETF in the secondary market ->IBIT is at a positive premium in the secondary market ->AP sells its IBIT inventory and buys BTC for hedging ->AP goes to BlackRock to apply ->T+1 delivery, AP gives BTC to BlackRock, BlackRock deposits it in the reserve wallet, and BlackRock transfers IBIT to AP