Banks have been applying negative interest rates to deposits from corporate and institutional customers for some time, but it now appears that they're about to extend that to retail deposits, starting at a high level of savings.
Savings are expensive business when you can't lend money out the door to pay for them. Looks right now as if Irish banks are depositing all the covid-19 related deposits with the ECB (at negative rates). Why wouldn't they look too recoup that. Especially with they've to pay their own operating costs on top of that.
The future of Ulster Bank raises the question will they appear sooner rather than later. Banks and vulture funds will be falling over each other to get the loan book but the deposits will likely stay in the banking sector. Worst situation for the remaining banks are liabilities go up (as deposits flood in) but they are out bid for the loan book. Means more money for banks to get charged for at the ECB (or invested in negative yielding government bonds).