Something like Fidelity's Cash Management Account (has a debit card, automatically liquidates money market funds to cover spending) works fine as an emergency fund. But you need your emergency fund in two separate accounts at two different financial institutions to be safe from shenanigans like this.

This is not merely a theoretical risk. Patelco (a Bay Area credit union with half a million members) got hit with ransomware back in 2024 that disrupted banking services for two weeks.

You can have multiple accounts, yes; but you can also diversify via friends and family.

As a good friend, if I know that you are good for the money, I'd happily spot you even a few tens of thousands for a few days or weeks. (I'm actually more reluctant to do that with some family members, because I might be less likely to get the money back.)

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