The price of a an individual medallion (see the price data here!) reached doubled to a record-high of $588,000 in February since 2004, while that of a corporate-owned medallion reached a another record high $779,000 in January. In fact ownership of this asset has yielded above-market returns of 20.75% per year for corporate medallions and 15.32% for individual medallions.
In 1937, the number of taxicab medallions was limited to those that existed at that time and by late 1940s this number had settled at 11,787. However, since 2003, State and local legislation have allowed the Taxi and Limousine Commission (TLC) to sell new medallions, bringing the current total to 13,257 yellow medallion taxicabs operating in New York City. In a ratio set by law, 40% of the total medallions are designated for individual, as opposed to corporate, ownership. Individual owners are required to drive at least part time, while corporate owners have the option of hiring an agent to lease the medallion full time for up to $800 a week.
If there are any derivative instruments based on the medallions, I would like to put my money there!!
Update 1 (24.1.2011)
Felix Salmon on the rise and rise of tax medallions,
"When the stock market peaked in October 2007, medallions were trading at $425,000 apiece. (All data from this page.) By the time the market had plunged by more than half in February 2009, medallions had risen in value to $552,000. And they’ve only gone up in value since: in December 2010, the average medallion changed hands for $624,000; last Wednesday, a new all-time record was set for a corporate medallion which sold for $880,000."