You could automatically import a table from the web into the sheet, or alternatively create some custom data types for currency conversion.

Or you could act like you're responsible for tens of millions of dollars and hand it over to someone who can make sure it doesn't blow up.

"We don't need to hire an electrician to wire up the office, I did my garage using uninsulated wires and it works perfectly!"

The guys handling millions of dollars should be trained in finance / accounting, so they aren’t untrained.

Handing over to IT usually means their flexible spreadsheet that they can change as they require, turns into an expensive and inflexible black box that only IT can change and that doesn’t integrate with the rest of their decisions. Also the new solution also probably has errors and pulls currency info from the same endpoint. Excel isn’t perfect, but it’s used for a reason.

To use your analogy, You can wait for an electrician to change your lightbulb, but that means your going to be working in the dark for longer.

Lightbulbs do not generally cost millions when they go out.

are you suggesting programmers don't hardcode URLs in quick-and-dirty (and sometimes, even production) Python scripts/code?

I'm suggesting they have logs.

logs of what? if a programmer hard-codes URLs, you really think they are following best practices elsewhere? further, how do logs help get back the millions of dollars that were lost?

Yes, logging with email alerts means that when a catastrophic error is encountered you'd know about it, instead of it being hidden for months.

LOL! as I already stated, a weak coder isn't going to implement best practices for logging. At best, he hard-coded his own email address to receive an alert, however, this also goes unnoticed, since, as you stated initially, he's dead.

Look, whatever company this was, was relying on YAHOO as its data source for making million+ dollar trades -- not Reuters, or Bloomberg, or JP Morgan, but YAHOO -- and then, for MONTHS -- not hours, or days, but MONTHS -- nobody in its finance department or trading desk or whatever happened to notice that the incoming data feeds were not matching up with quotes from counterparties, market makers, CNBC, colleagues, Wall St Journal? Does this company not have auditors? A CFO? Any IT oversight whatsoever? I'm sorry to say that this particular company's problems are rooted much, much deeper than the loss of a particular Excel guy.