Black Friday might be the day we associate with bargains on the shelves, but this year, prices were slashed in the stock market, too. 

A new COVID-19 variant has emerged in South Africa, and while we await more information about whether it's more severe than prevalent strains, investors have opted to take shelter after governments in Europe immediately imposed travel restrictions. 

It can be unnerving seeing the broad S&P 500 market index down over 2% in a single day, but it's not all bad news. Here's one stock that actually does well during periods of market volatility, and another stock you should accumulate for the long term either way.

An investor looking at stock charts on their computer monitors with confusion.

Image Source: Getty Images

1. The case for Interactive Brokers

Online broking giant Interactive Brokers (NASDAQ:IBKR) is no stranger to wild stock market swings. The company has been in business for 43 years, navigating events like the Black Monday market crash in 1987, the dot-com bust in 2000, and the Global Financial Crisis in 2008. 

But during the early parts of 2021, it experienced an unprecedented growth phase in its business amid the meme-stock frenzy driven by retail traders. In January 2021, it opened a record 116,100 new accounts, which was 689% more than it opened in January 2020. And since the start of 2020, it has more than doubled its client accounts overall to 1.58 million. 

Interactive Brokers' client assets have also more than doubled since January 2020, from $176 billion to $380 billion today. It suggests investors are not only growing more comfortable with owning stocks, but might actually be enticed by periods of market volatility. When it comes to broking, the amount of financial assets in client accounts is key, because brokers typically earn fees based on the volume traded. More assets means more volume, which equals more revenue.

While overall growth has slowed down from the lofty levels of January this year, most metrics still remain elevated.

Metric

October 2019

 October 2020

 October 2021

New accounts opened

7,200

26,300

46,300

Total shares (stocks) traded

12.4 billion

27.0 billion

42.6 billion

Total client assets

$162.1 billion

$232.6 billion

$380.9 billion

Data source: Interactive Brokers.

Analysts anticipate almost 33% growth in the company's earnings for the full year 2021. Should it meet expectations, it will have delivered $3.31 in earnings per share, placing the stock at a price-to-earnings multiple of 22. By comparison, the S&P 500 trades at a multiple of 28, and the Nasdaq 100 a multiple of 35, so the stock is much cheaper than the overall market. 

However, the upside for investors could come in the form of prolonged market volatility caused by concerns about the new COVID-19 variant. That makes Interactive Brokers a great buy in uncertain times.

A person signing a digital tablet with a lady of justice statue on the desk.

Image source: Getty Images.

2. The case for DocuSign

DocuSign (NASDAQ:DOCU) is a pandemic-market darling. As the leading digital signature platform, investors in its stock have been rewarded with returns of 230% since January 2020, as the stay-at-home economy demanded innovative new tools to keep the economy turning. If there's ever a resurgence of COVID-19 restrictions, this company could be in a great position to capitalize.

Yet even if there isn't one, its diversification into other business verticals over the last couple of years makes it a favorable long-term investment. For instance, its DocuSign Insight platform leverages artificial intelligence to read and analyze legal contracts to identify troubling clauses, or even beneficial ones. 

While it's not ready to replace your lawyer, it has the potential to be a major cost-saving tool, particularly for businesses that issue and receive a high volume of legal paperwork. 

Further, the DocuSign Negotiate for Salesforce platform can generate customized agreements, then act as a collaborative contract negotiating tool between internal and external parties who can make adjustments in real time.

The effects of remote work in the stay-at-home economy on this company are apparent through its revenue and earnings growth compared to fiscal 2019 (DocuSign's fiscal year ends Jan. 31). 

Metric

Fiscal 2019

Fiscal 2022 (Estimate)

CAGR

Revenue

$701 million

$2.09 billion

42%

Earnings per share

$0.09

$1.70

166%

Data source: DocuSign, Yahoo! Finance. CAGR = compound annual growth rate. CAGR = Compound Annual Growth Rate

DocuSign's ramp-up in earnings per share comes partly from diversifying its business, and partly from achieving scale through its more than 1 million paying customers. Rapidly growing revenue combined with a high gross margin (which hovers around 80%) means the company can aggressively invest in growth, as fixed costs are quickly becoming a smaller portion of overall sales -- leading to the powerful rise in earnings. 

While the COVID-19 situation remains uncertain, DocuSign is shaping up to be a great long-term investment that could also offer protection for your portfolio if things do take a negative turn

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.