What you should worry about is reducing the various risks you face by:
1) Having at least 2 distinct banks with no overlap in who has admin access. This is the most important step. In the US, an insider at your company is way more likely to commit fraud or get phished than your bank failing. Just like you’d never operate your production app from one availability zone, never rely on one bank.
2) If you have $10mm or more, consider having a portion of your funds at each bank going into a money market sweep. These off balance sheet facilities might take a few days or more to access from an operational standpoint during a bank failure, but are not subjected to the bank’s credit risk. However, money markets have their own different risks so I’d never recommend having more than 50% in them.
3) If you have more than 36 months of runway, having a portfolio of T-Bills. While U.S. Treasury Bills are often referenced as “risk free”, that ignores the fact that they can lose resell value, purchasing and holding them often involves some sort of counterparty risk, and there is always operational risk.
Please do not use one of the big four banks. It is just making the system less safe, and there are plenty of times when that decision is going to bite you (a la PPP in 2020).
For specific recommendations:
1) A credit union or community bank with a branch you can readily access. While you should never have to go in-person, it can be really useful to have it as a backup option.
2) If absolutely wanted to go with a big bank, Capital One is not a bad option.
The top 3 are JPM-Chase, BoA, and Citi.
Kindof like making sure you have backups and they work.
I like https://mercury.com and have been using them for a few years. It's a bank wrapper, but your money is in a real bank (Evolve bank). [0] I recommend them because:
* $1M FDIC insurance for your cash [1]
* Business banking features I use work great (paying vendors, receiving wires)
Me, I would look into local banks and do some hard work "research" and pick one of them. They tend to be more tuned into you community. Maybe a Credit Union ?
If you are worried about bank runs you can divide your deposits into $250,000 chunks and divide it between banks. (or whatever the insured amount in your country is)
Then do treasury management. Put excess cash in short term treasury bonds (and their non-US equivalents). These are backed by the full faith and credit of the issuing country and the markets in them are very liquid. I’m sure there is some service that will automate this for you, for a small fee.
Are holdings in money market funds/accounts in such typical brokerages protected / owned like a security? Or should one regard it also like cash, and not FDIC insured greater than $250,000? (but while also trusting those institutions are unlikely to fail or have risky policies)
Good liquidity...