Investors should keep an eye on the number paying subscribers for Bumble , according to Jefferies. Analyst Brent Thill downgraded shares of Bumble to hold from buy, expecting dwindling revenue growth, among other challenges, for the online dating company. "While our 3P data checks show an acceleration in Q2 rev and downloads for the Bumble App we still see several reasons to be cautious at current levels," Thill wrote. The analyst expects decelerating average revenue per paying user (ARPPU) growth going forward, forecasting just 1% growth in fiscal year 2022. Meanwhile, Thill finds it unlikely that Bumble's margin expansion will soon catch up to competitor Match Group. "Finally, we no longer view BMBL's valuation multiple at 26x FY23 EBITDA as compelling especially compared to MTCH at 18x. We lower our FY22 EBITDA estimate by 1% to account for incremental FX headwinds," Thill wrote. To be sure, Thill raised Bumble's price target to $39 from $30, roughly in line with Friday's closing price for the company. Shares declined 0.8% in Monday premarket trading. —CNBC's Michael Bloom contributed to this report.