Cedara Software Corp. of Toronto is being acquired by Merge EFilm of Milwaukee in an all-stock deal worth about $476.6 million, the companies announced Tuesday.

Merge EFilm, a global health-care software and services company, said it will issue either 0.587 of one of its common shares, or 0.587 shares of a newly created class of Canadian exchangeable shares, for each common share of Cedara, an independent developer of medical software technology.

The deal is valued at about $15.10 for each common share of Cedara. The companies said the offer includes 17.5 per cent premium to Cedara's 20-day volume weighted average stock price.

Cedara shares closed Monday up seven cents at $13.92 on the TSX. But the takeover deal barely moved Cedara stock. It was off 2 cents to $13.90 in trading on the TSX on Tuesday.

Merge EFilm shares were off 6 cents US, closing at $19.49 US on Nasdaq.

The deal is expected to close in April.

The corporate headquarters for the combined company will be in Milwaukee, Wisc. Richard Linden, Merge EFilm's president and CEO, will hold those positions in the new company, while Cedara president and CEO Abe Schwartz will serve as a member of its board of directors.