Artificial intelligence lending company Upstart Holdings (UPST 2.76%) has stumbled since reporting its second-quarter earnings. Shares are down by more than 55% since the end of July.

The company turned in a clunker of an earnings report in this high-interest rate environment, something I elaborated on a couple of weeks ago. But here I am waving the stock's flag -- and I promise you I'm not as crazy as I seem today.

There are problems at Upstart, but I'm holding for the long term because of two significant product expansions just starting. Here is what they are and why the stock can still be a long-term winner.

1. Significant momentum in the automotive space

Upstart, which uses artificial intelligence to evaluate consumers' creditworthiness, started its business in personal loans. But it began branching out two years ago when it acquired Prodigy, an automotive retail software company, for $58 million. Since then, Upstart has integrated its lending technology into Prodigy and relaunched it as Upstart Auto Retail, an all-in-one software suite that can streamline automotive sales at dealerships, from sales to financing.

The early momentum has been promising. Automotive Market Data, a research survey that contained dozens of competitors, named it the fastest-growing automotive retail software last summer. Nine automotive brands have authorized Upstart Auto in the United States, including brands like Mercedes-Benz, Honda, and Volkswagen. There are currently 61 dealerships offering Upstart-powered loans, up from 39 the previous quarter.

Not only is automotive lending a big market, estimated at $755 billion, but the company is walking down the risk ladder a bit. Personal loans could be considered more risky because an asset doesn't secure them. While automotive loans carry risks, there is at least an asset to back the loan.

Upstart currently holds $413 million in auto loans on its balance sheet for research purposes, establishing cohort data it can present to prospective loan buyers as it grows this product category. Moving forward, investors should see the number of dealerships offering Upstart loans growing.

2. HELOC loans carry enormous potential

Moving to increasingly secured loan categories, Upstart is just beginning to test home equity lines of credit (HELOC loans). You can think of this as similar to a credit card -- it's a line of credit you can borrow against, creating a balance owed. But with a HELOC, your home is the collateral backing the loan.

In August, CEO Dave Girouard discussed HELOC loans in the company's Q2 earnings call, stating that this product will target prime borrowers (higher credit quality). Speed and automation will be Upstart's value proposition to home equity borrowers; according to Girouard, Upstart targets a closing process of less than five days, versus the industry's average of more than one month.

Since homes are an enormous consumer asset, the addressable market is significant, too. Upstart estimates that mortgages are a $2.2 trillion market, so there's a long path for growth if the company succeeds. It's testing this product in Colorado and will follow that with other states over the coming months.

3. In it for the long-term

These two massive growth opportunities are genuinely in their early days. It could take several years to gauge how successful Upstart is, encouraging shareholders to think with a long-term mindset. Investors will want to see more dealerships offer Upstart-powered loans moving forward and more states offering HELOC loans.

In the meantime, Upstart must grapple with a challenging economic environment that has stunted personal loan volumes without sufficient demand for the loans it can approve. To be clear, Upstart is a speculative investment at this point. However, one should acknowledge the upside, should Upstart successfully navigate these rough waters.

The ride could be bumpy, but there's still a lot of potential here looking years down the road, which is why I'm holding shares.