Two city taxi medallions have been sold on the private market for a record-breaking $600,000 each - showing demand for the scarce licenses is stronger than ever.

The buyer operates a fleet of yellow cabs and closed the deal last month, according to the company that made the loan, Medallion Financial Corp.

The value of the metal shields has been climbing steadily in recent years - up from $195,000 in 2001 - outperforming the stock market and even red-hot real estate.

The reason is that the city strictly limits the number of medallions. There are 13,087 in circulation now, but only 1,300 of them have been auctioned in the past 70 years.

Bidding at the rare auctions has been frenzied, and the top price at the last one in June 2006 was $554,148.

Medallions bought at auction can be resold on the private market. The name of the seller and buyer in the latest sale were not disclosed.

The city applauded the inflationary trend.

"This record sale price says that the New York City taxi industry is healthier and more vital than ever before," said Taxi and Limousine Commissioner Matthew Daus.