The company said Wednesday its board is committed "to delivering superior value for shareholders and all stakeholders" and will pursue all initiatives to that end.
"Osisko's board of directors noted that the 15 per cent premium to Osisko's unaffected share price implied by Goldcorp's offer is very low and the price opportunistic in light of Osisko's proven high quality asset base," the company said in a statement.
Osisko urged shareholders to hold off from accepting the $2.6-billion bid until the board, which has formed a special committee including five independent members to review the offer, makes a recommendation on the proposal.
Osisko shares have traded well above the $5.95 implied value of the Goldcorp offer since the stock-and-cash proposal was first announced on Monday.
Analysts have suggested that Goldcorp will have to raise its offer if it wants to close the deal.
Osisko shares closed up two cents at $6.25 on the Toronto Stock Exchange on Wednesday, while Goldcorp was down six cents at $24.28.
Osisko's main asset is the Canadian Malartic gold mine in northern Quebec where it has been ramping up operations since its first commercial production in May 2011.
In addition, Osisko owns the Hammond Reef gold project near Thunder Bay, Ont., and land holdings near Kirkland Lake, Ont.
Goldcorp was once one of the largest shareholders in Osisko, but sold its 10.1 per cent stake in the company in 2011 for $13.75 per share for a total of about $530 million.
Since then, the big gold producer said it had been in regular discussions with Osisko until late last year.
The acquisition of Osisko would give Goldcorp a key asset in Quebec where the company is building the Eleonore gold mine.
Goldcorp chief executive Chuck Jeannes has said Canadian Malartic would rank among his companies' best operations if the takeover is successful.