Airbnb's (NASDAQ:ABNB) December IPO comes at a calculated time. The coronavirus pandemic has battered the tourism industry, sending the peer-to-peer accommodation company's revenue down 32% year over year to $2.5 billion and expanding its operating loss to $490 million in the nine months ending September 2020.

The public listing gave Airbnb a much-needed capital infusion of $3.5 billion and allowed early investors to cash out of their positions. But with a market cap of $101 billion at the time of writing, new investors could be left holding the bag if Airbnb doesn't live up to the market's lofty expectations.

Let's dig deeper to see if the stock is worth adding to your portfolio.

World map with money on it.

Image source: Getty Images.

The coronavirus isn't going away anytime soon

As a vacation rental company, Airbnb's business model relies on a robust travel and tourism industry. Research company Statista estimates tourism declined by 42% in 2020 because of the adverse effects of the coronavirus pandemic. And the industry may experience continued headwinds in 2021, despite the rollout of COVID-19 vaccines. 

According to data from John Hopkin's University, the coronavirus pandemic may be accelerating around the world. And some countries won't have broad access to vaccines until 2022. Among countries that do have access to vaccines, progress in administering those vaccines has been painfully slow. Dr. Anthony Fauci estimates that 85% of the U.S. will need inoculation in order for the country to attain herd immunity, but only 3% of the populace has received the first jab at the time of writing. 

Nevertheless, Airbnb as a company has recovered from the worst impacts of the crisis. Third-quarter revenue is down 18% year over year to $1.34 billion, which is a significant improvement from the 72% year-over-year decline in the second quarter. But the company still faces a very uncertain future, which calls its optimistic valuation into question. 

Airbnb's stock seems priced for perfection

With a market cap of $101 billion compared to 12-month sales of $3.6 billion, Airbnb boasts a price-to-sales (P/S) ratio of 28, which is significantly higher than the hotels and tourism sector average P/S of 4. The good news is that Airbnb's asset-light business model can give it an advantage over its rivals.

Unlike traditional hotels, Airbnb shifts most accommodation-related expenses to hosts on the platform. This strategy helped keep operating costs relatively stable over the last two years. Airbnb also slashed its marketing budget amid the pandemic, leading to a $419 million operating profit in the third quarter. However, the third-quarter profit may still not be enough to justify the stock's sky-high valuation.

Airbnb has historically experienced significant seasonality (with revenue and profit dropping in the fourth quarter). And many of its cost-cutting measures, including reduced executive salaries and marketing expenses, may reverse when the pandemic ends.

Airbnb stock is not a buy 

Investors love to bet on growth stocks with disruptive business models because of their potential for long-term success. But while Airbnb is an exciting stock to watch, it doesn't look like a good investment right now because of potential overvaluation.

The company is already priced for perfection despite facing significant uncertainty from the coronavirus pandemic, and investors should wait until some of the hype dies down before considering the addition of Airbnb to their portfolios. 

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.