According to an analysis by HVM Capital, the disruption in the taxicab business caused by upstart car-for-hire firms such as Uber and Lyft is only beginning, and warns investors to be wary of stocks in corporations financially exposed to taxicab medallion prices.

Most vulnerable, according to the report, are companies such as Medallion Financial, Signature Bank and multiple credit unions and other specialty lenders that lend money for purchases and, in the case of some, ownership of taxi medallions – the government-controlled taxi permits.

The values of taxi medallions throughout the country have plummeted between 20% and 40% over the last year, a trend HVM said will continue.

“Medallion markets are absorbing the sudden incursion of unconstrained vehicle-for-hire capacity that is lower-priced, higher-quality and offers better customer service,” according to the report. “Cities and states across the US have overwhelmingly opted for acceptance and regulation rather than elimination, and courts have rejected invocation of takings or eminent domain arguments for medallion owner compensation after medallion values collapsed.”

Medallion Financial, for example, has $689 million of managed loans collateralized by taxicab medallions (53% of total managed loans), and owns 150 medallions in Chicago, the market most vulnerable to near-term collapse, valued at $49 million but worth $33 million at current medallion prices.

“We believe once it is clear to market participants that supply constraints have been permanently eliminated and exclusive access once conferred by medallions is gone, taxicab medallions will eventually be worthless,” said the report’s author, James F. Hickman of HVM Capital. “Any company with heavy concentration in this area, such as Medallion Financial, is looking at a severe financial reckoning.”

To view the full HMV report, click here.