Shares of Ribbon Communications Inc. (RBBN) plummeted 5.65% in pre-market trading on Thursday, following the release of the company's second-quarter earnings report. Despite posting better-than-expected revenue, investors appeared to react negatively to unchanged earnings per share and potentially soft third-quarter guidance.

Ribbon reported Q2 adjusted earnings of $0.05 per diluted share, unchanged from the same period last year and in line with analyst expectations. Revenue for the quarter ended June 30 rose to $220.6 million, up from $192.6 million a year earlier and surpassing the $213.4 million forecast by analysts polled by FactSet.

However, the company's outlook for the third quarter may have spooked investors. Ribbon expects Q3 revenue to range from $213 million to $227 million, with the midpoint falling below the $225.2 million anticipated by analysts. This guidance, combined with the flat earnings per share, suggests that Ribbon may be facing challenges in translating its revenue growth into improved profitability, potentially due to increased costs or a less favorable product mix.