(Adds details on specific stocks, updates prices)
* TSX down 58.64 points, or 0.4 percent, to 14,667.22
* All of the TSX's 10 main groups move lower
TORONTO, Oct 3 (Reuters) - Canada's main stock index fell on Monday in a broad retreat led by its heavyweight financial and natural resource sectors.
The financials group slipped 0.5 percent, as Canada's finance minister prepared to make an announcement about the country's housing market, which could include measures aimed at cooling interest from foreign buyers.
Investors were also more cautious as Britain set a March deadline to start its withdrawal from the European Union and worries over Deutsche Bank continued to swirl.
The most influential stocks weighing on the index included Royal Bank of Canada, which fell 0.6 percent to C$80.76, and Bank of Nova Scotia, down 0.6 percent to C$69.12.
At 9:59 a.m. EDT (1359 GMT), the Toronto Stock Exchange's S&P/TSX composite index had fallen 58.64 points, or 0.4 percent, to 14,667.22.
All of the index's 10 main groups were in negative territory, with more than 4 decliners for every advancer.
Shares in fashion retailer Aritzia Inc were trading at C$18 in their market debut, after they were priced at C$16 last week.
The energy sector retreated 0.3 percent as oil prices slipped back, while the materials group, which includes precious and base metals miners and fertilizer companies, lost 0.6 percent. Those two sectors account for a combined one-third of the index's weight.
The financial sector accounts for more than one-third.
Gold prices were little changed, while copper prices declined 1.4 percent to $4,798 a tonne, as funds that had pushed prices for the metal, used in power and construction, higher in September reduced their positions.
Shares in Spectral Medical Inc slumped 78 percent to 35 Canadian cents after it said its experimental treatment for sepsis - a common, often deadly complication of infection - failed a late-stage study, stymieing the company's plans to bring to market the first U.S. Food and Drug Administration-approved device for the condition. (Reporting by Alastair Sharp; Editing by Jonathan Oatis)