I try to find out who pays the profit of a lucky CFD transaction. When mrX buys a long CFD with underlying value of 10.000€. Now as I understand the CFD is not covered by actual shares, so mrX doesn't own the refered shares. The refered shares only seem to play the role of random generator of value of the CFD. Now suppose the value of the refered shares rizes to 11.000€, who is paying the 1000€ profit for mrX? I can't imagine the broker, they would not want these risks.
At first I thought: the broker has a mrY buying a short CFD linked to the same shares and with about the same value then mrY pays the profit of mrX, but this chance is too small.