What happened?

Shares of Carvana Co. (CVNA 4.86%), a used car retailer with unique car vending machines, as well as an online car buying and financing platform, are down more than 13% Friday afternoon despite a lack of direct news. Here's what could be happening.

So what

Investors might simply be able to file Friday's decline under "sometimes stocks go up, and sometimes stocks go down." But there could be a few other factors at play here, such as mainstream and institutional investors taking some profits. After all, the stock is up almost 100% year to date and has had an incredible run since its initial public offering (IPO).

CVNA Chart

CVNA data by YCharts.

Now what

Investors can likely expect volatility like this as investors and analysts choose their side of the Carvana story. On one hand, you have long-term investors buying into the business model and believing that its growth, albeit expensive, is the right move. Carvana's growth in the first quarter was impressive: retail units sold increased 99% compared to the prior year, revenue jumped 100%, total gross profit increased 159%, and Carvana entered its 100th market.

Carvana's eight-story car vending machine.

Image source: Carvana, Co.

On the flip side, all of Carvana's growth came at a price and its debt has increased since going public. Carvana ended the first quarter with cash and cash equivalents of about $85 million.

When you consider that the company's interest expense has ballooned $12.1 million from last year to reach $15.6 million during the first quarter, you can see why there's concern about the company's balance sheet. Some investors might be taking profits with the stock's year-to-date gains, believing that the company's cash burn could push the company to raise capital and thus dilute shareholders.

Whether you're long or short Carvana, pops and drops like Friday's will likely keep happening, so take them with a grain of salt and keep your bull or bear thesis fresh and updated.