Dockwise says the offer undervalues its business and that some Dockwise shareholders think the price is too low.

"To stop the nagging they could raise the price by 1 or 2 euros. Investors only risk losing one or two dimes. Boskalis can offer any price, they have a lot of money," Tom Muller, analyst at Dutch private bank Theodoor Gilissen, says.

With about 40 million Dockwise shares outstanding, and Boskalis already owning 33 percent of the company, a higher offer would only cost a few dozen million euros more, Muller says. (Reuters)