Uber's stock fell 7.6 percent on Friday, its first day as a publicly traded firm. The bloodbath continued on Monday, with Uber's stock price falling by an additional 10.7 percent.

It's a sobering moment for the ride-hailing company. As recently as last October, some Wall Street banks were estimating that the company could be valued as high as $120 billion. At Monday's closing price of $37.10, Uber is worth barely half that, at $62 billion. (The company is worth around $68 billion on a "fully diluted" basis, which counts stock options and other assets that could eventually be converted into shares.)

Monday wasn't a good day for the broader stock market either, but the Standard & Poor's 500 fell a comparatively modest 2.4 percent.

Uber's top American competitor, Lyft, fell 5.7 percent, valuing the company as a whole at $13.8 billion. The company's stock has lost a third of its value since its March IPO.

Uber has never made an annual profit, and in recent quarters, the company has been losing more than $1 billion per quarter. The company has justified those losses by pointing to its rapid growth. Some of those losses have reflected efforts to expand into new markets as well as aggressive research and development spending.

Until recently, investors seemed to be happy to continue covering Uber's losses in hopes of owning what they hoped would be a hugely profitable technology company. Indeed, Uber raised $8.1 billion in extra cash in its initial public offering—a sum that will last the company about two years at its current burn rate. But Wall Street's patience won't last forever. Uber CEO Dara Khosrowshahi is going to face growing pressure to make good on Uber's long-promised path to profitability.

Lyft is in a similar predicament. It's a significantly smaller company, so its market capitalization, losses, and cash cushion are all proportionately smaller. But like Uber, Lyft has seen mounting losses along with rapidly expanding revenue. And before too long, the company needs to demonstrate that it can turn a profit.