For lotteries in particular, it&#x27;s a little unclear. The lottery-playing public seem to love gigantic jackpots (just see all the press when a jackpot grows obscenely large. Why would a small-time player buy more tickets to win $100 million, but not bother to buy a ticket to win $1 million? But still they do...) , and the more lottery companies out there, the more distributed the money becomes, leading to smaller jackpots and thus fewer players. So the difference between licensing one lottery and several might not be much.<p>(I wonder if any has done studies on this? There must be some &#x27;optimal&#x27; (for tax revenue) number of lotteries for a jurisdiction)