Oct 19 (Reuters) - Canada's main stock index was muted on Monday, as investors weighed weakness in energy shares against gains in the materials sector and renewed optimism around a U.S. stimulus deal.

* At 9:45 a.m. ET (1345 GMT), the Toronto Stock Exchange's S&P/TSX composite index was down 0.07% at 16,427.08.

* The materials sector, which includes precious and base metals miners and fertilizer companies, added 0.4% helped by firmer gold prices, while the energy sector dropped 0.3%.

* Ballard Power Systems Inc fell 2.2%, the most on the TSX, and the second-biggest decliner was Brookfield Business Partners LP, down 2%.

* Canadian wholesale trade increased by 0.3% in August from July on stronger sales in the building materials and supplies subsector, as well as motor vehicles and parts, Statistics Canada said.

* The financials sector slipped 0.2%. The industrials sector fell 0.2%.

* On the TSX, 102 issues were higher, while 112 issues declined for a 1.10-to-1 ratio to the downside, with 10.43 million shares traded.

* The largest percentage gainers on the TSX were toy-maker Spin Master Corp, which jumped 6.6% after National Bank upgraded the stock, and AltaGas Ltd, which rose 4.3%, after multiple brokerages raised the price target of the stock.

* The most heavily traded shares by volume were Nextsource Materials Inc, SOPerior Fertilizer Corp, and Orosur Minng Inc.

* The TSX posted one new 52-week highs and one new low.

* Across all Canadian issues, there were 17 new 52-week highs and two new lows, with a total volume of 25.31 million shares. (Reporting by Amal S in Bengaluru; Editing by Ramakrishnan M.)