Shares in Finland's biggest company were down by over 11 percent on Helsinki's OMX stock exchange on Monday, the first day of trading after a three-day weekend.
The stock ended the day at 1.71 euros, the lowest since Finland adopted the common currency.
Late on Thursday, Nomura analyst Rick Sherlund told Reuters that said Nokia's software partner Microsoft is looking at making its own smartphone.
Such a move would mean more competition as well as an awkward position for Nokia, which has placed all its bets for a turnaround on Microsoft's software.
Other analysts have also said the exclusion of Nokia's existing Lumia phones from Microsoft's new software, Windows Phone 8, may weigh on sales in coming months although the improvements may boost sales of future Lumia phones.
Samsung's positive surprise
There was further pressure on Nokia as rival Samsung upped its forecast for sales of its new Galaxy S III phone. Samsung also predicted handset earnings would be higher in the current second quarter than in January-March, countering market concerns that tight supplies would pressure earnings.
Last week Nokia began redundancy talks aimed at slashing its worldwide workforce by 10,000, with nearly 4,000 jobs to go in Finland.
Oulu & Salo need new employers
Labour Minister Lauri Ihalainen told Yle on Monday that more efforts must be made to attract foreign employers to the hardest-hit towns of Salo and Oulu. He noted that there are some 6,000 highly-trained IT professionals in two cities either looking for work or at risk of losing their jobs. Ihalainen added that Oulu and Salo also have excellent vacant space available and reasonable cost levels.