All but eight stocks on the Toronto Stock Exchange's S&P/TSX composite index <.GSPTSE> fell, and each of the 10 main sectors lost at least 1 percent in the sharpest selloff since January 5.

"When you have days like this it's really tough to hang on. You're looking at numbers being weaker and weaker by the minute," said Marcus Xu, president and portfolio manager at M.Y. Capital Management Corp in Vancouver.

He suggested investors do just that, on the thinking that the index could rise by year-end as the Greek crisis ultimately gets resolved and the U.S. Federal Reserve starts a long-awaited rate-hiking cycle.

The index ended down 317.94 points, or 2.15 percent, at 14,490.15.

Six of the seven most influential weights on the Canadian stock index were financial stocks, with Royal Bank of Canada (>> Royal Bank of Canada) falling 2.3 percent to C$76.47, Brookfield Asset Management (>> Brookfield Asset Management Inc) losing 4.3 percent to C$43.32, and Manulife Financial Corp (>> Manulife Financial Corp.) shedding 3.1 percent to C$23.14.

Without evidence of Greek exposure, the retreat may not be sustained.

"I don't think any Canadian bank has one dollar of assets in Greece anymore. If they do, shame on them because everybody knew about this four years ago," said Barry Schwartz, portfolio manager at Baskin Financial Services.

On the positive side, Element Financial Corp (>> Element Financial Corp) rose 1.7 percent to C$19.19 after agreeing to buy General Electric Co's (>> General Electric Company) fleet management operations in the United States, Mexico, Australia and New Zealand for C$8.6 billion.

The overall financial group dropped 2.5 percent, while energy stocks fell 2.4 percent and consumer names were off more than 2 percent. The best performing groups - industrial, telecoms and materials - were all down at least 1 percent.

"Today finally there is an excuse to sell, and of course the economically sensitive countries like Canada will be on the worse side of that," M.Y.'s Xu said, adding that slumping Chinese stocks were adding to unease. "I wouldn't step in right now."

A Reuters poll showed that strategists expect Canadian stocks to edge higher in the second half of the year before picking up further in early 2016.

(Reporting by Alastair Sharp; Editing by Peter Galloway and Richard Chang)

By Alastair Sharp