But some say it came from the long connection of the two animals -- bulls and bears -- in sports that were popular years ago in England.
Investors are always concerned about the possibility of a company failing.
In the modern world, a company that does not earn enough profit is said to go belly up.
A company that goes belly up dies like a fish. Fish turn over on their backs when they die. So they are stomach, or belly, up.
Stock market investors do not want that to happen to a company. They want a company whose stock they own to earn more profit than expected.
This would sharply increase the value of the stock. Investors are hoping for a windfall.
The word windfall comes from England of centuries ago. There, poor people were banned from cutting trees in forests owned by rich land owners.
But, if the wind blew down a tree, a poor person could take the wood for fuel. So a windfall is something wonderful that happens unexpectedly.
