In order to promote risky behavior, it is a common practice that casinos incentivize their customers through the provision of free financial means, i.e., free play. Thereby, casino operators try to exploit what is known as the house money effect. However, evidence from the field is scarce and prior research provides explanations that predict different behavioral outcomes. This experimental study analyzes the gambling behavior of 765 casino customers and finds that incentivized customers show not higher but significantly lower levels of risk-seeking behavior, expressed through lower wagers per game and overall smaller losses. This study thus provides evidence against the existence of a house money effect.