I had a couple inquiries about these chips yesterday... I don't know much about them
for sure, but here's what I have... I picked up 4 of these at the Casinorama show... the
obverse sides have an identical MGM-Mirage logo... the reverse sides have the names
of 4 different banks: Bank of Scotland, Citigroup, J.P. Morgan Chase, and U.S. Bank.

My guess would be that these were made up for a conference of investment bankers -
perhaps back when MGM-Mirage was trying to put together the financing for City Center
in Las Vegas.

Here are the front sides:

And here are the reverse sides:

If anyone has authoritative information about these chips, I'd love to have the info - thanks for looking.