You are incorrect. My article, although a bit unclear, was not wrong.

Taken right from the FDIC website at http://www.fdic.gov/deposit/deposits/insuringdeposits/

"The basic insurance amount is $100,000 per depositor per insured bank. Certain retirement accounts, such as Individual Retirement Accounts, are insured up to $250,000 per depositor per insured bank."

They further describe:

"You may qualify for more than $100,000 in coverage at one insured bank if you own deposit accounts in different ownership categories."

They then describe what the different ownership categories are:

"The most common ownership categories are: Single Accounts, Certain Retirement Accounts, Joint Accounts, Revocable Trust Accounts" (obviously this is not a complete list)

And lastly, single accounts were described as:

"These are deposit accounts owned by one person and titled in that person’s name only. All of your single accounts at the same insured bank are added together and the total is insured up to $100,000. For example, if you have a checking account and a CD at the same insured bank, and both accounts are in your name only, the two accounts are added together and the total is insured up to $100,000.

Note: Retirement accounts and qualifying trust accounts are not included in this ownership category."

So what this all says is:

  You may have a total of $100,000 in your combined Single Accounts (checking, savings, etc)
  You may have a total of $250,000 in a qualifying IRA.
  You may have a total of $100,000 in a trust. (Although trusts get more complicated, this is not entirely true).
  You may have a total of $100,000 in a joint account, your partner another $100,000.

Since this is not a complete list, I can't blankly say that you can have up to $550,000 at one bank.

By the way, thanks for all the comments here on my article and at the article itself. Was a real treat to see the activity yesterday!

I meant to post this under seiji's reply.

It's per depositor per bank. If you have 10 accounts each with $100,000 at one bank, you are only covered for $100,000.

(That may be what you said with "each bank's accounts," but the article is definitely mistaken).

I wrote a response above that clarifies this misconception. I've talked with a lot of people in person over the last 2 months about the FDIC insurance, and I'm surprised as how many people actually get this wrong. In any case, you are incorrect when you said my article was mistaken. I may not have described it clearly (read other response above for clarification), but it was not mistaken.

In the UK you are insured up to £35k (soon £50k) per person per FSA registation.

As multiple trading names operate under one registration (E.g. Lloyds & Scottish Widows) you have to be careful.