AI Olympics 1999

Virtual Stock Market Documentation




The Event/Scoring

Each team gets $1 Million to trade for the duration of the Olympics. You may divide this up in any way you wish: allocate $100K to individual investors, collaborate on trading decisions, or fight it out as one team member sells the shares another had bought seconds earlier...

The goal, as always, is to accumulate as much wealth as possible as fast as possible. If any shares are held when the contest ends, they will be sold at the last day of trading's closing bid price. A team's score is the amount of money remaining, plus a participation bonus: I will add in $10,000 for each team member who made a trade on the system. (The exact value of the bonus may be changed after a couple days of trading, depending on the teams' performance, to make it a fair contest.) Each person should make trades from their own machine, as extra verification that they are who they say they are.


Basic Functions

Viewing Your Portfolio
Simply follow the links from the main page, identify your team and enter your team's password (your team subcaptain should have this). The portfolio is displayed and time stamped. The prices are current as of the time of the request (the time stamp), and are NOT updated automatically. To update the prices without making any trade, click the "Discard Order; Update Prices" button. (Note this clears any fields you've typed in; hence, the "Discard Order" part.) Alternately, you can submit a "blank" form (without any changes, or in the reset state) to get updates on your team's portfolio.

To view your team's trading histories for a stock, click on the symbol name. Below the table there is also a comprehensive list of all symbols ever traded by your team for this purpose.

Pricing
To get the current reported prices for a symbol you don't hold, execute a transaction on 0 items of it; the symbol will show up on your next portfolio report only, and then will disappear. The easiest way of making a 0-share transaction is to just enter the symbol in one of the new entry fields below; you don't actually need to enter a number or change the transaction type. To keep it around for another update, where it's listed with the other stocks, just click one of the transaction types for it before submitting.

Buying/Selling
To buy or sell something you already hold in your portfolio, on the line where the item is listed simply check "Buy" or "Sell" and enter a volume (note the default volume is your entire holdings of that item -- be careful!). For new symbols, enter the symbol in one of the "New Order" lines at the bottom of the form, and do the same. (You can also enter a symbol in one of the lines below even if you already hold it.) The symbol is re-priced when the order is submitted; this means that the actual price of your transaction may not be exactly what is shown on the form you're submitting, especially if the form is at all old.

Note that there are two prices listed, a bid and an ask, which are different for many symbols. You buy at the ask price and sell at the bid. The spread between the two means that if you buy and then immediately sell (or vice versa, if you already hold it) you've instantly lost some money. This is not because of what you normally think of as brokers' commissions for the sale, which would cause additional losses on top of the bid/ask spread losses; there are no brokers' commissions in the VSM, with the explicit intent of encouraging trading by the teams. (The bid-ask spread is collected by the "market makers," who organize the trading for that particular security, and the virtual market makers are no less avaricious than their corporeal counterparts. What, you think I do this for free?) You can trade any time, even if the markets are closed; the most recently reported prices are used for the transaction.


Details of the Interface


The Data Feed

The pricing data is fed over the net and is the standard 15-20 minute delayed data. It is possible to cheat by getting a real-time feed and playing the time lag; THIS IS EXPLICITLY CHEATING and goes against the spirit of the event; don't do it.

The data has fairly extensive coverage over the range of tradeable securities and has many derivative instruments. If you can find a symbol for something, there's a good chance we can get data on it; try it. The advertised categories include:

For the last two, the first character for the symbol is often a caret, a "^". For example, the Dow is ^DJI and the S&P 500 is ^SPX.

Finally, note that I do not get information about stock splits. Should a stock you hold split during the event, you've just lost half your money in that stock! (And should there be a reverse split, you double your money.) If you know of any good online source of (machine-readable) splitting data, please let me know.


Greg Galperin (grg@ai.mit.edu)