Carvana Co. (CVNA) is headed to the big leagues. The online used car dealer will join the S&P 500 index as part of the quarterly rebalance, and if you're scratching your head wondering how this happened instead of some flashy tech company, you're not alone.

Index Shuffle Season

Carvana will officially join the S&P 500 within the next two weeks, sharing the spotlight with CRH Plc (CRH) and Comfort Systems USA (FIX). Making room for the new arrivals means some companies have to go, and this time it's LKQ Corp (LKQ), Solstice Advanced Materials (SOLS), and Mohawk Industries (MHK) getting the boot.

The S&P Dow Jones Indices made the announcement Friday as part of its regular quarterly rebalancing act across the S&P 500, S&P MidCap 400, and S&P SmallCap 600 indices. Investors clearly liked what they heard—Carvana stock popped 9.81% in Monday's premarket session.

This follows another recent addition to the index: Sandisk Corporation (SNDK) joined on November 28, replacing Interpublic Group (IPG).

The Plot Twist Nobody Saw Coming

Here's where things get interesting. Most investors had their money on bigger tech names or even a crypto play making the cut. The rumor mill was churning with speculation about Strategy (MSTR), Marvell Technology (MRVL), and even Reddit (RDDT) potentially landing S&P 500 spots. Instead, we got an online used car dealer.

But maybe it's not as shocking as it seems. Carvana has been on an absolute tear lately. Earlier in December, the company's shares surged after Wedbush analyst Scott Devitt upgraded the stock, pointing to strong recent results and a credible roadmap to hitting three million annual unit sales by 2033. That's a pretty ambitious target, but the market seems to be buying the story.

Why Carvana's Moment Makes Sense

Carvana's business model lives and dies by borrowing costs, especially for subprime and lower-prime customers who make up a significant chunk of their buyer base. With the Federal Reserve signaling potential rate cuts ahead, the company's prospects suddenly look a lot brighter. Lower interest rates mean cheaper car loans, which means more customers can afford to buy vehicles through Carvana's platform.

The numbers back up the excitement. Carvana is sporting a momentum rating of 84.70% and an eye-popping growth rating of 99.15%. That growth metric evaluates the company's historical earnings and revenue expansion across multiple timeframes, weighing both long-term trends and recent performance. When you're in the 99th percentile for growth, you're doing something right.

On a year-to-date basis, Carvana stock has climbed 100.33%. That's the kind of performance that gets you noticed by index committees, even if it means beating out the tech darlings that everyone assumed were shoo-ins.

The S&P 500 addition will likely bring a fresh wave of buying pressure as index funds and ETFs adjust their portfolios to match the new composition. For a company that was fighting bankruptcy concerns not too long ago, this is quite the comeback story. Whether Carvana can maintain this momentum remains to be seen, but for now, the used car dealer is driving in the fast lane.