What happened

Shares of BioNTech (BNTX 0.07%) were trading down by 17.6% as of 11:50 a.m. EDT on Tuesday. The German biotech didn't announce any news that would explain such a decline. Its COVID-19 vaccine partner, Pfizer (PFE -1.05%), even raised its 2021 sales forecast for BNT162b2 to $26 billion. So why did BioNTech's shares slide?

The most likely reason is that the mood of the overall stock market is weighing on this biotech stock. Some investors could also be taking profits off the table after BioNTech's big jump Monday on news that BNT162b2 could have an accelerated path to market in India.

Blue line with arrow trending down next to a coronavirus virion and stock prices in the background

Image source: Getty Images.

So what

It's important to remember that even after factoring in BioNTech's Tuesday morning decline, it's still up by more than 110% year to date. Some volatility is to be expected with high-flying stocks.

There are more reasons to be optimistic about BioNTech's prospects, though. Pfizer and BioNTech already have sealed deals to supply their COVID-19 vaccine to Canada and Israel beyond 2021. The companies are talking with other countries about similar agreements.

Now what

BioNTech could give investors a reason to jump back into the stock soon. The company is scheduled to announce its first-quarter results on May 10. Based on Pfizer's Tuesday update, BioNTech should have impressive revenue growth to report.