Discovering an IPO price

Since the launch of the simExchange, stocks and futures contracts have debuted at a price suggested by the submitter of the game with some adjustment by the admins of the simExchange. This price was generally too high or too low, resulting in sharp price moves following the IPO and windfall profits. This is expected as the forecast of an individual inefficiently aggregates information compared against a market. Although many traders have come to expect windfall profits from an IPO (possibly from the irrational exuberance of the 90s tech bubble), this is not how an IPO is supposed to work.

To remedy this problem, the simExchange began the use of an experimental new IPO process to determine the IPO price. We evaluated many IPO processes such as Dutch auctions and Parimutuel Auctions but decided on a Double Call Auction to keep the process simple. A double call auction is how trading on the simExchange has always functioned. The only difference from standard trading is that the automated market maker is turned off.

Price discovery works through traders submitting buy orders at the maximum price they are willing to buy at and submitting sell orders at the minimum price they are willing to sell at. Essentially, traders are posting a range of how well they think the game will sell—a maximum and a minimum.

For a single trader, this range may be very large. They may think a game will sell a minimum of 400,000 copies (40 DKP) and a maximum of 600,000 copies (60 DKP). This would equate to a buy order at 40 DKP and a sell order at 60 DKP. With this player’s orders alone, the bid-ask spread is a very large 20 DKP.

However, a second trader may believe the game will sell at least 500,000 copies (50 DKP) and at most 650,000 copies (65 DKP). The trader’s orders represents a 15 DKP bid-ask spread, but together with the other trader, the best bid is now 50 DKP and the best ask is now 60 DKP. The bid-ask spread is now 10 DKP.

A third trader believes the game may only sell 300,000 copies (30 DKP) with a max of 550,000 copies (55 DKP). The bid-ask spread is now 5 DKP. The order book would look like this:

As more traders submit orders, the bid-ask spread will tighten and converge on a market price. Individually, no one knows what the IPO price should be, but together, traders can narrow the range down substantially. This price range should be the best guess of a fair IPO price as this is where the buyers and sellers meet (the optimists and pessimists for the game’s potential sales). In this IPO process, trades only occur when traders are willing to buy and sell at the same price. Once again, this is no different from normal trading except there is no automated market maker submitting orders.

However, this process has proven to be difficult to understand for many members of the simExchange, especially those who use the Basic Trading mode, which is limited to placing market orders (orders that immediately take the best available price). If a trader is not used to looking at what is the current selling price, he may be in for a surprise when his buy order fills.

Originally we had considered reserving the IPO process only to those using the Advanced Trading interface so that traders are forced to identify the matching price they would accept. However, we thought traders using the Basic Mode should still be allowed to participate if they see a price they think is good for buying or selling. Of course, this assumes the trader using the Basic Trading mode is paying attention to the current bid and ask prices. However, many traders using the Basic Trading mode ended up with prices they were not happy with.

Last night, we have heard a deep debate regarding the IPO process. Our goal is to make accurate forecasts in an entertaining and easy to play process. It appears the experimental IPO process has failed to accomplish those goals for many traders.

Based on user suggestions, we will combine the experimental process with elements of the original IPO process into a 2-step IPO process. Once a stock or future is listed on the simExchange, there will be a stage to determine the IPO price. This will be a three-day period in which players place orders in a double call auction. To participate in the double call auction, the player must specify the maximum price he will buy at or the minimum price he will sell at. After the three-day period, an IPO price will be calculated. At this point, the second stage will occur with the stock or future available for purchase or shorting at the IPO price all day by all traders. Following this day, regular trading with automated market maker will commence.

Please post discussion on this issue here rather than the general forum. Remember, this is an experimental process in determining the best way to IPO a contract on a prediction market.