Canwest, Canada's largest media group, fell 23 cents a share, or 9.09 percent, to close at $2.23 a share.

UBS Securities Canada strategist Garry Cooper said Canwest stock would be deleted from the Standard & Poor's/TSX composite index at the close of business Sept. 19 if its value continued to fall. Canwest's market capitalization appeared below the criterion for continued inclusion in the index, Cooper said.

Large institutional investors typically dump large corporate stocks that slip from the index.

Canwest stock has fallen 63 percent this year, with the losses attributed to a weakening advertising outlook and Canwest's $3.7 billion debt, The Globe and Mail reported.

Chief Executive Officer Leonard Asper, who heads up the founding and controlling Asper family, is considering taking the Winnipeg, Manitoba, company private with the help of major shareholder Fairfax Financial Holdings Ltd., the newspaper said.

Fairfax, a Toronto financial services holding company, owned 16.29 percent of Canwest's voting shared March 9.