One point is that hsbc might not be acquiring all of the liabilities – they might mostly get customer deposits but not eg some unsecured loan or bond issue. Regulators could be ok with such an outcome because a bunch of businesses losing bank deposits may be seen as worse than a single company defaulting on its debt.

Another is that SVB UK could be solvent so long as they don’t have to sell assets at a loss. Being part of hsbc stops the assets needing to be sold at a loss. And a separate thing is that even if the assets net liabilities are negative, the customer relationships could be valuable enough to hsbc to counteract that. Hsbc get a load of growing companies whom they can try sell banking services to. That assumes customers don’t all flee, but I don’t think they would because there isn’t a particular reason to fear hsbc in the way there was for SVB.

I don’t know what the commenter meant about JPM printing money.

They acquired a bunch of client assets for 1 GBP. Those client assets will generate money for them in the long term. For HSBC this is a great deal. For the clients too, come to think of it. On Friday the future of their money was uncertain, whereas today they can relax a bit because a big bank is backing them.