Billionaire energy mogul Bill Koch is looking to cash in on Aspen’s red-hot luxury real estate market by listing his ...

You’ll have to boast a particularly robust bank account to nab billionaire Bill Koch’s newly listed wintry Colorado retreat.

Now, it appears that billionaire Bill Koch, sibling of Tea Party darlings ... It's on secluded Oyster Island, with a main residence, guest house, tennis court, lawns, gardens, and orchards.