After holding the top spot in the global smartphone market for years, Nokia may soon lose its dominance to Samsung and Apple, according to an investors' note from Nomura Securities.

Sometime this quarter, the investment firm expects Samsung to grab first place, followed by Apple in second, a move that would shake up a landscape led by Nokia since 1996.

"We are forecasting that Samsung takes the No. 1 position in smartphones in Q2 (fractionally) and that it extends this lead in Q3," said Nomura. "This represents a significant turnaround from a 4.8 percent share in 1Q10 to 20.4 percent in Q3 2011."

At the same time, Apple's smartphone unit share will remain steady at around 17 percent, but Nokia's is expected to drop from its current 25 percent to about 16 percent. Beyond the current quarter, Nokia will continue to shed market share, according to Nomura, and could be be overtaken by HTC by the end of next year.

Hit by competition and a difficult market, Nokia recently slashed its sales forecast for the second quarter. The company also is in an awkward position for now as it tries to transition from its own operating systems to Windows Phone, courtesy of its recent deal with Microsoft.

Nokia is pinning much of its hopes on Windows Phone, but Nomura doesn't see the company's fortunes improving anytime soon.

"Market shares in mobile phones have swung greatly in prior years and so a come-back from Nokia is feasible, in our view," Nomura said. "However, we see no evidence of a product led turnaround and continue to see better opportunities among Asian vendors in particular."

Though it's slated to take second place as a global smartphone maker, Apple faces its own own brand of challenges, said analyst Richard Windsor of Nomura, speaking last week at the Open Mobile Summit. Pointing out that gross margins in the smartphone industry are too high, Windsor expects a move toward less pricey units.

"We see the handset market becoming much more competitive," Windsor noted. "The number of people who'll pay $500 or $600 for a smartphone [the wholesale price before carrier subsidies] is rapidly running out."

New growth will come from Asian Android phone makers such as LG Electronics and HTC, forcing Apple to decide if it wants to jump onto the cheaper phone bandwagon, a potential move that would be at least a year away.