Shares of Finnish telecommunications firm Nokia dropped around 3 percent on Monday after analysts at Goldman Sachs downgraded the stock from “neutral” to “sell.”

Analysts Alexander Duval and Hameed Awan wrote in a note that Nokia faces downside risks amid increasing competition from Swedish rival Ericsson and South Korean tech giant Samsung.

Nokia shares have outperformed the broader European tech sector by roughly 2 percent over the past 6 months, as investors hoped the rollout of new 5G wireless networks would boost the Finnish firm’s revenues. The Goldman analysts said investors might be too optimistic about Nokia given the company’s own projections for a slow start to the year.

“We believe there is scope for further downside to consensus, as our new estimates now factor in lower network revenues, a more conservative margin trajectory and more muted growth in the highly profitable patents business,” the analysts said.

Goldman estimates Nokia and Chinese tech giant Huawei each capture 23 percent of the global wireless networking market, compared to Ericsson with 29 percent of market share. Samsung trails well behind the top three players with 5 percent of the market.

But Samsung is stepping up its efforts to provide network equipment as super-fast 5G wireless networks start to roll out globally. Analysts at Goldman noted Samsung has already partnered with operator Verizon to provide 5G equipment in the U.S., adding the South Korean firm could double its market share in coming years. They said Samsung’s gains could especially present risks for Nokia.

“We see Samsung’s success in gaining share in the U.S. as major validation of the quality of its technology, particularly at Verizon, one of the world’s most advanced 5G players,” the analysts said.

Goldman estimates Nokia and Chinese tech giant Huawei each capture 23 percent of the global wireless networking market, compared to Ericsson with 29 percent of market share. Samsung trails well behind the top three players with 5 percent of the market.

But Samsung is stepping up its efforts to provide network equipment as super-fast 5G wireless networks start to roll out globally. Analysts at Goldman noted Samsung has already partnered with operator Verizon to provide 5G equipment in the U.S., adding the South Korean firm could double its market share in coming years. They said Samsung’s gains could especially present risks for Nokia.

“We see Samsung’s success in gaining share in the U.S. as major validation of the quality of its technology, particularly at Verizon, one of the world’s most advanced 5G players,” the analysts said.