Economic uncertainty has sent the S&P 500 and the Nasdaq Composite tumbling into bear market territory, and many growth stocks have lost more than half of their value during the ongoing decline. For instance, shares of Block (SQ 0.71%) and Atlassian (TEAM -1.37%) have dropped 78% and 74%, respectively, leaving both stocks near a 52-week low.

However, some Wall Street analysts see that as a buying opportunity. Joseph Vafi of Canaccord has a price target of $150 per share on Block (SQ 0.71%), which implies 192% upside from its 52-week low of $51.34. And Gregg Moskowitz of Mizuho has a price target of $255 per share on Atlassian (TEAM -1.37%), implying 124% upside from its 52-week low of $113.86.

Is it time to buy these growth stocks?

Block: A disruptive financial services company

Block simplifies financial services for businesses and consumers with its Square and Cash App ecosystems. Square is a connected suite of hardware, software, and banking solutions that help businesses grow across physical and digital channels. The cohesive nature of those products distinguishes Block from traditional merchant-services providers (like banks), which generally bundle products from different vendors, leaving sellers to deal with complicated integrations.

Block brings that same simplicity to consumer finance. Cash App allows users to spend, borrow, and invest money from a single platform. That broad functionality helped Cash App become the most downloaded mobile finance app in the U.S. during the first half of 2022, but Block has only scratched the surface of its long-term vision.

In the third quarter, Block reported solid financial results in spite of economic headwinds. Gross profit climbed 38%, representing particularly strong growth in the Cash App ecosystem. Non-GAAP (adjusted) earnings rocketed 68% to $0.42 per diluted share.

Looking ahead, Block puts its addressable market at $190 billion in gross profit, and management is executing on a strong growth strategy. Since acquiring the buy now, pay later (BNPL) platform Afterpay earlier this year, Block has made BNPL an option for all Square sellers, both in person and online. Building on that, Cash App consumers will soon be able to use the digital wallet to browse products and make purchases from Afterpay and Cash App Pay merchants. That could spark a powerful network effect. As commerce functionality brings more consumers to the Cash App, businesses are more likely to accept Afterpay and Cash App Pay, and vice versa.

Currently, shares of Block trade at 2 times sales, just above the three-year low of 1.7 times sales. That makes this growth stock a screaming buy.

Atlassian: A leader in team collaboration and productivity software

Atlassian specializes in work-management software. Its portfolio includes a number of tools -- Jira for product management, Confluence for knowledge management, Trello for task management -- that help enterprises plan, track, collaborate, and complete work more effectively.

Atlassian primarily distributes its software online without a traditional sales force, meaning it relies heavily on word-of-mouth marketing. That strategy keeps its sales and marketing costs low, allowing the company to invest aggressively in research and development. That advantage has helped Atlassian develop a broad portfolio of integrated products, many of which have become the gold standard in their respective markets.

For instance, Jira is the leading product-management and bug-tracking software, and Confluence is the leading knowledge-management solution, according to G2 Grid. Likewise, research company Gartner recently named Atlassian a leader in enterprise agile planning tools, and Forrester Research named Atlassian a leader in enterprise-service management.

The company reported reasonably strong results in the first quarter of fiscal 2023 (ended Sept. 30, 2022). Revenue increased 31% to $807 million, and free cash flow climbed 31% to $75.9 million. But investors should prepare for turbulence in the near term. Management issued Q2 guidance that fell far short of Wall Street's consensus forecast, noting that customer growth is slowing as businesses pull back on IT spend. That news sent the stock into a nosedive.

Fortunately, the deceleration should be temporary, and the investment thesis remains sound. Atlassian is a key player in several software verticals, and it has a sizable runway for growth. In fact, management says its products are relevant to 2.2 million businesses worldwide, which equates to a $29 billion addressable market.

With that in mind, shares currently trade at 10 times sales -- the cheapest valuation in three years. That make this growth stock an attractive investment idea right now.