Do CFD brokers need to have an actual connection with the trade markets and which exchanges do the prices come from?

I'm trying to figure out why CFDs exist. Do they have any actual connection with the markets or are they just like gambling sites. Where do they take the prices from and how do they augment them and is that regulated ? I didn't manage to get enough information from Google on these questions, so I hope the hive mind here can help.

Submitted July 15, 2017 at 03:18PM by stargazer_w http://ift.tt/2tXnwSI