Informed Traders' Profits under Different Definitions of Insider Trading
The volumes of the two cone-shaped solids represent the total profits of informed traders. (Actually the profits are the sum of the vertical sections along price and trade-size: the profit is the distance of price from true value times the number of shares bought.) As time progresses, additional traders may obtain the information, therefore those who have the information trade more aggressively.
The aggressive trading is most visible in the outer (frame-wire) solid, where informed trading starts after significant competition has developed. The large trades push price to its destination (true value) fast, not allowing the informed traders to derive much profit.
The inner solid represents the informed profits without a prohibition of insider trading. The monopolist traders (insiders) know they do not have competition and place very small trades, maximizing their profits by preserving false prices for their subsequent trades.
The point is that informed profits are reduced by prohibiting trading of insiders while their information is exclusive. See Georgakopoulos, Insider Trading as a Transactional Cost.