Regardless of the ups and downs of the stock market, companies with innovative businesses driving change in their respective industries present compelling opportunities for investors. If you're on the hunt for these types of businesses to buy as 2024 kicks off, you don't have to look far to find intriguing investment opportunities that can make wise additions to your portfolio for the long term.

Here are three such stocks to consider hitting the buy button on before 2024 gets any further.

1. Intuitive Surgical

Intuitive Surgical (ISRG 0.59%) is trading up by roughly 60% from its position one year ago. About a third of that share price gain has been realized since the start of 2024. The company dominates the surgical robotics space globally, and has done so since its first da Vinci surgical system was approved more than two decades ago.

Intuitive Surgical sells several models of its flagship da Vinci surgical system, which is approved for use in a wide range of minimally invasive surgeries. It also has the Ion system in its portfolio, which has non-surgical use cases as it is approved specifically for minimally invasive lung biopsies.

Broadly speaking, Intuitive's business focuses on five surgical areas: urologic surgeries, cardiothoracic surgeries, head and neck surgeries, general surgeries, and gynecologic surgeries. Based on currently approved uses for its systems, management has noted that there are more than 70 clinical uses for its various da Vinci surgical system models.

Even as hospital systems and other medical providers are spending more cautiously in the current macroeconomic environment, Intuitive Surgical's installed base of systems has been growing at a steady clip, driving revenue and profits skyward.

As of the end of 2023, Intuitive Surgical reported that it had 8,606 da Vinci surgical systems installed globally. The lion's share of those systems -- 5,111 to be exact -- are installed in the U.S., while 1,617 are in Europe, 1,484 are in Asia, and 394 are distributed across other client markets. That overall installed base figure of 8,606 systems was up 14% from one year ago, and a whopping 54% from four years ago.

Intuitive brought in revenue of $7.1 billion in 2023 and earnings of $1.8 billion -- increases of 14% and 35%, respectively. A rock-solid healthcare business with a robust runway for growth still ahead, and solid footing in a wide addressable market isn't always easy to find. In Intuitive Surgical's case, this company is waving multiple green flags that may entice investors to scoop up some shares.

2. Airbnb

Airbnb (ABNB 0.75%) is trading up by a double-digit percentage year to date, and has risen by close to 30% over the trailing 12 months. The travel platform continues to rake in revenue, profits, and cash flow at an enviable clip, and at a far higher rate than many other growth-oriented businesses. There are likely multiple reasons behind this overall resilience.

Airbnb serves both sides of the travel accommodation dynamic. On the one side, it provides a platform for hosts around the world to list their homes and properties, while on the other side, guests with just about any type of travel requirement can find accommodation to suit their needs. In the third quarter, active listings jumped 19% year over year, while guests booked 113 million nights and experiences, a 14% increase. Meanwhile, Airbnb hosts earned more than $19 billion.

Airbnb started releasing biannual platform upgrades two years ago, and has launched hundreds of additional features since that time. Recent upgrades include better pricing tools for hosts, reduced prices on long-term stays, new categories of cost-effective stays, and improvements to search tools. Airbnb is benefiting from a strong recovery in cross-border travel, but it's also witnessing steady gains in markets that were previously underpenetrated by its platform. For example, gross nights booked in Korea in the third quarter were 54% higher than in the same quarter of 2019, before the pandemic.

In addition to the flexibility of Airbnb's platform as well as the benefits it offers to both hosts looking to make an income and guests searching for any variety of stays, the company facilitates these bookings at very little overhead cost. Airbnb doesn't own the properties listed on its platform. This asset-light model is continuing to drive meaningful growth on the top and bottom lines.

Revenue rose 107% from four years ago to $3.4 billion in Q3, while net income for the three-month period totaled $4.4 billion, compared to a profit of $266 million four years ago and a profit of $1.2 billion one year ago. There's a lot of growth opportunity left for this business within the broader travel space, and its differentiated platform is driving incredible profitability. Investors may want to take advantage of this buying opportunity before the stock shoots higher.

3. Upstart

Upstart Holdings (UPST 2.76%) is down so far in 2024 although the fintech stock is up by an eye-popping figure of more than 100% over the past year. The company has reported significant declines in revenue as well as a lack of profitability in recent quarters due to a steep downward trajectory in loan volume.  Elevated default rates, higher interest rates, and the overall heightened lending risks are making lenders more hesitant to fund loans than they were in the past, and consumers are more hesitant to apply for loans as well.

This has created a perfect storm for many companies with broad exposure to the lending space. Upstart is no exception. The company primarily makes money from fees attached to servicing loans, so of course when loan volume and funding are down, this is going to have a deleterious impact on its balance sheet. It's also important to note that the decrease in loan volume on Upstart's platform isn't just a function of the macro environment as a whole, although default trends are undeniably a key factor here.

Upstart isn't your average lending platform. It uses artificial intelligence and machine learning to evaluate would-be borrowers based on over 1,500 variables that its model uses to determine their creditworthiness. Because this model considers many factors beyond those that go into the traditional FICO score, Upstart has been able to approve more loans than the average bank at lower annual percentage rates, but without hurting its lenders' risk profiles. In turn, lenders have gained access to previously untapped pools of potential creditworthy borrowers.

Given the ongoing risk baked into the macro environment, Upstart's model is approving far fewer borrowers now. These elements will take time to adjust, but given how Upstart's model calibrates to the environment at hand, more favorable lending tailwinds should gradually right the ship. Loan volume was up 5% sequentially in the most recent quarter. Model accuracy is also key to Upstart's growth. Its personal lending platform recently experienced the most significant upgrade in five years, improving model accuracy by around 15%.

In the meantime, more lenders are joining Upstart's platform, and it is growing an active presence in various lucrative areas of the multi-trillion dollar addressable lending market, including auto loans, personal loans, and mortgages. The next several quarters could still be pretty ugly. However, the potential of this business, which has few direct rivals that compete at its scale, could make it worth scooping up even a modest position as part of a well-diversified portfolio.