Monday was an up-and-down day on Wall Street, as major stock market indexes found themselves on either side of the unchanged line before closing on mixed notes. Investors appear to be waiting to see what steps the Federal Reserve will take with interest rates in the next couple of months, and they'd also prefer more clarity about whether U.S. trade disputes with major trading partners will get resolved favorably. Some stocks took big hits on a combination of general nervousness and company-specific issues. PayPal Holdings (PYPL 0.20%), Okta (OKTA 0.81%), and PaySign (PAYS 3.29%) were among the day's worst performers. Here's why their stocks did so poorly.

PayPal falls with payment stocks

Shares of PayPal Holdings closed down around 5% on a generally bad day for payment processing stocks. The industry has been a beneficiary of the rise of electronic payment transactions  internationally, but pressures on the global economy have the potential to drag on the growth of PayPal and its peers. Nervousness about the company's ability to keep growing as quickly as investors had been expecting it to has plagued investors ever since the company released its second-quarter financial results back in July. Yet even after Monday's decline, the stock is still up more than 25% from where it stood in early January.

Building with PayPal logo on glass in atrium.

Image source: PayPal Holdings.

Okta falls back

Okta's stock dropped 10% on a day when investors seemed to be reassessing the prospects of the software-as-a-service industry more broadly. Many stocks that rely on recurring revenue as an essential element of their business models came under pressure Monday, but Okta's current decline started late last week. That was in part due to an offer that extended key maturities of Okta's debt in exchange for the immediate issuance of shares of stock to bondholders as well as replacement debt. The enterprise security and identity protection specialist still has plenty of growth potential, but shareholders seem to be boosting their assessments of the company's riskiness as well.

PaySign cuts its guidance

Finally, shares of PaySign dropped 21%. The prepaid card program provider and processing company said that it now expects its full-year 2019 revenue to come in between $35 million and $37 million. That's down from its previous guidance range of $38 million to $40 million. Even with the downgrade, PaySign still anticipates top-line growth of 50% to 58%, and it reaffirmed its belief that adjusted pretax operating earnings will more than double this year. Yet investors weren't happy to see sales growth slow, taking it as another sign that the company might be vulnerable to changing economic conditions.