1. Fast-Paced Trading of Multi-Attribute Goods Eugene Fink Josh Johnson John Hershberger

2. Motivation Build an automated exchange for trading goods and services Combine the speed of the stock exchange with the flexibility of eBay +

3. Previous work Combinatorial auctions Standardized exchanges - Complex goods - Asymmetry between buyers and sellers - Illiquid - Simple goods - Symmetry between buyers and sellers - Liquid

4. Research goals Build an automated exchange for non-standardized goods. Allow complex constraints in the specification of desirable trades Support fast-paced trading for markets with millions of orders

5. Outline Multi-attribute orders Search for matches Experimental results

6. Market A market is a set of items that can be bought and sold. Example: A car market is a set of all possible vehicles.

7. , –$1 for every ten miles. ; Mustang for $28,000 or Corvette for $32,000 Orders An order is a subset of the market along with a price function. Example: Any Mustang or Corvette

8. Orders Price Buy order Sell order Price

9. A buy order matches a sell order if: There is item buy-items  sell-items, such that buy-price(item) sell-price(item). Matching Price Buy order Sell order

10. Attributes A specific market is defined by a list of attributes. Example: A used-car market is a set of all possible vehicles, defined by model, year, and mileage.

11. An item specification may include lists of values and numeric ranges. Buy order Model: Mustang Year: 2001..2003 Mileage: 0..10K Example: Sell order Model: Mustang Year: 2003 Mileage: 0 Attributes A trader specifies acceptable items by attribute values.

12. Attributes 00 01 02 03 Year Model Price CamryMustang Corvette Buy order Model: Mustang Year: 2001..2003 Sell order Model: Mustang Year: 2003

13. Outline Multi-attribute orders Search for matches Experimental results

14. Main structures Tree of fully specified orders Unordered list of the other orders

15. Model CorvetteMustang Indexing tree Mileage 50K 1996 Mustang, 50K miles, $7,000 1988 Corvette, 20K miles, $4,000 20K1996199719881986 Year

16. Model CorvetteMustang Indexing tree Mileage 50K 1996 Mustang, 50K miles, $7,000 1988 Corvette, 20K miles, $4,000 20K 19961988 Year Camry 1999 Mileage 1999 Camry, 10K miles, $18,000 10K Mileage 2000 2000 Camry, 180K miles, $5,000 180K

17. Depth-first search Model Mileage Year CorvetteMustang 1996 50K 1996 Mustang, 50K miles, $7,000 Year Camry 1999 Mileage 1999 Camry, 10K miles, $18,000 10K Mileage 1988 1988 Corvette, 20K miles, $4,000 20K Mileage 2000 2000 Camry, 180K miles, $5,000 180K Buy Order: Any car made after 1990 Best price

18. Outline Multi-attribute orders Search for matches Experimental results

19. Performance : 2 GHz CPU 1 Gbyte memory 166 MHz bus Experiments using a Pentium computer

20. Cars and bonds Car market with eight attributes : 4,000 to 20,000 orders per second bonds Bond market with two attributes cars number of orders orders per second 10 2 10 3 10 4 10 5 10 1 10 3 10 4 10 5 10 2 : 1,000 to 5,000 orders per second

21. Artificial markets number of attributes 1 310 30 100 orders per second 10 2 10 3 10 4 10 5 Synthetic market data: 1 to 100 attributes 300,000 orders

22. Summary General model for trading of multi-attribute goods Fast identification of matches between buy and sell orders