Finnish insurer, Sampo, has agreed to buy Topdanmark in an all-share deal worth 33bn crowns ($4.73bn).
Sampo already owns 48.5% of the Danish P&C insurer.
"By combining the businesses in a fully integrated Nordic operating platform, we can unlock growth and attractive synergies that will strengthen our position as a leading Danish P&C insurer," Sampo CEO Torbjorn Magnusson said.
The companies said they expect the acquisition to result in annual cost savings of €65m for the merged group and a further €30m in higher income per year.
Topdanmark said the proposed tie-up would give its owners the opportunity to take part in a well-diversified Sampo with strong growth perspectives.
"We find that the offer from Sampo represents attractive financial value for the shareholders of Topdanmark," the Danish group's deputy chair Jens Aalose said.