August was an up-and-down month for the Nasdaq-100. At first, the tech-focused index continued its rising trend from July before peaking mid-month and ending at a lower point than it started. However, this was just the composite index, not its individual components. Some had great months, while others didn't fare as well.

That may get investors thinking, "Are the worst-performing stocks good buys in September?" Let's dig in and see if these stocks are worth purchasing.

Match Group

Taking the prize for the worst-performing Nasdaq-100 stock in August was Match Group (MTCH 0.79%). It lost nearly 28% of its value in August, which points to some pretty extreme news.

Match Group is the parent company of many top dating apps like Tinder, Match, and Hinge. It makes its money through two methods: subscriptions and advertisements. Anyone following the economy knows advertising businesses aren't doing the best. Still, Match Group's indirect revenue (ad revenue) rose 7% year over year in its second quarter. Overall, revenue rose 12% year over year, with particular strength in the Asia-Pacific region (which grew 32% year over year).

This business performance didn't stop the stock from dropping nearly 18% after it reported earnings -- likely due to comments about the acquisition of Hyperconnect (a video connection service) made last year. CFO and COO Gary Swindler had this to say about Hyperconnect: "But there's no denying that that acquisition of Hyperconnect has not worked out the way we had hoped, at least in the first year."

That's not a reassuring comment, but management has also committed to better integrating this acquisition and realizing its full potential.

In the meantime, Match Group's profitability will take a hit (it posted a negative operating margin in the quarter due to $217 million in intangible expenses from the Hyperconnect acquisition). Despite these expenses, the stock trades for 33 times free cash flow, making it relatively cheap when you factor in Match Group's current business state of digesting an acquisition.

I think investors can find some value in Match Group's stock, especially after its terrible August performance.

Splunk

Moving to the second-worst performer, Splunk (SPLK) dropped 23% in August. For the most part, Splunk's August wasn't terrible until it reported fiscal year 2023 Q2 results on Aug. 24.

At face value, results for Splunk seemed positive. Its data processing platform that aids in business decisions saw total revenue rise 32% year over year to $799 million, and cloud revenue grew 59% to $346 million. But this quarter's performance wasn't the problem.

Investors took issue with Splunk's guidance. It decreased its annual recurring revenue (ARR) and cloud ARR from $3.9 billion to $3.65 billion, and $2 billion to $1.8 billion. Missing projections on the downside is a surefire way to generate negative sentiment, which is why the stock fell nearly 20% from when it reported earnings to the end of the month.

However, with Splunk trading at less than five times sales, there's little valuation risk. But with management revising growth estimates down, I'm more hesitant to give Splunk the green light.

Dollar Tree

The value store Dollar Tree (DLTR -0.14%) had a similar experience in August. Again, it was smooth sailing until it reported earnings, then it all went downhill on Aug. 25, causing the stock to slide nearly 20%.

While the overall quarter was good, guidance was to blame for the stock's tumble. In Q2, earnings per share (EPS) was up 30.1% year over year against sales growth of 6.7% -- solid results for the retailer.

As for guidance, management stated it is committed to competitive pricing and is investing in its merchandising and store standards to achieve this goal. Because of this, management reduced its EPS outlook -- but to a level that still indicates 25% year-over-year growth.

At under 20 times earnings, Dollar Tree is cheaper than competitors Walmart (26 times earnings) and Dollar General (23 times earnings) despite growing faster from an EPS perspective in Q2. As consumers' dollars are squeezed more due to inflation, they may turn to value stores to stretch their funds further.

Because of that, I think Dollar Tree may be undervalued compared to its growth and performance, and investors should consider this stock.