The share price of Norway Royal Salmon (NRS) fell sharply Thursday, a sign investors and insiders believe last week's takeover offer from rival SalMar won't likely go through.

Shares of Norway Royal on the Oslo Stock Exchange fell well below NOK 270 (€26/$30.60) -- the offer from SalMar to take over the company -- as SalMar CEO Gustav Witzoe and Aker Group's Kjell Inge Rokke, two of Norway's richest people, launched a large-scale collaboration on offshore salmon production.

In late afternoon trading, shares of Norway Royal had fallen by 6 percent to around NOK 260 (€25.10/$29.50).