Not exactly an Excel question, but "$10MM" was used in an Excel
question posted in these newsgroups.

What exactly does $10MM mean?

In a Google search for $10MM, I found two online news articles in
which $10MM was in the headline, but the text spoke of "10 million
dollars".

If it means "10 million dollars", as I suspect, why not write $10M?

When I look at $10MM, I think of "10 million million dollars" -- that
is, 10 trillion dollars (10^12).

But the context of the Excel question suggests to me that that is not
what was intended.