When Starbucks (SBUX -0.17%) reports fiscal 2021 second-quarter earnings on Tuesday, it's going to be in stark contrast to last year's results. The pandemic had hit this large-cap company hard in 2020, and this quarter is likely to be a major turnaround.

As of April 19, all Americans age 16 and up were eligible to receive a coronavirus vaccine, and roughly 50% of the population has gotten at least one dose. The U.S. is Starbucks' largest market, with a total of 46% of all stores. Meanwhile, in its other major market, China, the number of people getting infected with COVID-19 has declined significantly from peak levels.

If you're interested in Starbucks stock, here are three things you're going to make note of from the April 27 earnings report.  

A Starbucks employee at a drive thru handing out a drink.

Image source: Starbucks.

1. How are comps recovering? 

First, take note of the overall comparable-store sales, which declined by 5% year over year in the first quarter. The revenue figure, which excludes the effects of new store openings, is key in determining consumer demand for its products. Starbucks has guided investors to expect comps growth between 18% and 23% for the second quarter.

The return to growth will be a welcome sign for a company that's been hard hit by the pandemic. Still, Starbucks is not firing on all cylinders as people continue working, learning, and entertaining themselves at home to a far greater extent than pre-pandemic.

2. What's the operating margin?

In the first quarter, Starbucks saw its operating margin declined to 13.5% from 17.2% at the same time last year. The pandemic is impacting margins in two ways: decreasing sales and increasing store-level costs.

Elevated expenses will be around for a while longer, but Starbucks will get some help on margins from increasing revenue as consumers start venturing out more often. Moreover, the company is adding substantially more locations internationally than domestically, in part because those locations come with higher profit margins.

3. How is the economy's reopening affecting store traffic?

Finally, you'll want to hear what management has to say about changes in customer habits as business restrictions are being lifted in the U.S.

Business reopenings gained steam in the first quarter of 2021 as more and more people are getting vaccinated. Folks feel a little more comfortable leaving their homes, and that could be a boom for Starbucks. Still, millions of people continue to work from home, which hurts sales because morning commuters are more likely to stop by to grab a coffee and a breakfast snack. 

What this could mean for investors 

Analysts on Wall Street expect Starbucks to report quarterly revenue of $6.78 billion and earnings per share of $0.53, which would be increases of 13% and 66%, respectively, from the same time last year. The future looks bright for the worldwide coffee chain, but the positive outlook could already be reflected in the stock price.

Starbucks' stock price is already up 10% year to date as investors anticipate a solid rebound in revenue and earnings in 2021. If the company misses earnings estimates or sounds pessimistic about the rest of 2021 when it reports its second-quarter results, share prices could pull back. But for those with the long-term investment horizon to allow for Starbucks to get back to full strength, any price drop can be treated as a buying opportunity.