The cash offer of 265 kronor per share values OMX at some 32 billion kronor ($4.9 billion).
OMX operates exchanges in Copenhagen, Stockholm, Helsinki, Reykjavik, Riga, Tallinn and Vilnius.
Böcker, announcing third quarter results, said the offer should close in late February.
The company reported a net profit of 223 million kronor for the three months to September, up 34.4 percent from a year earlier, as revenues rose 22.6 percent to 1.00 billion kronor.
“The third quarter was yet another strong quarter for OMX,” the company said in a statement.
In late September Borse Dubai and Nasdaq, then rivals to take over OMX, said they had joined forces to acquire it together in a deal that gives Borse Dubai 19.99 percent of US-based Nasdaq and 28 percent of the London Stock Exchange.
In a complex takeover proposal that ended months of speculation over OMX’s fate, the groups said Borse Dubai of the United Arab Emirates would follow through on its previously announced 230 kronor per share offer for OMX. The August 17 bid valued the group at $3.97 billion.
The US-based Nasdaq stock market would then acquire all of Borse Dubai’s OMX shares.
Then on September 26 they said they had sweetened their takeover offer and had secured 47.6 percent of its shares.