* TSX falls 103.47 points, or 0.68 percent, to 15,162.57
* Energy drops 3.1 percent to hit a 14-month low
* Cenovus slumps 10.5 percent to C$9.20
* Seven of the TSX's 10 main groups decline
TORONTO, June 20 (Reuters) - Canada's main stock index fell on Tuesday as energy shares dived with oil prices, while Cenovus Energy Inc tumbled after the company announced plans to replace its chief executive.
Cenovus said it will replace Chief Executive Brian Ferguson, who championed an unpopular purchase of western Canadian oil sands assets, though it failed to name a successor, sending its shares tumbling 10.5 percent to C$9.20.
The overall energy group fell 3.1 percent, hitting its lowest since April last year, while oil prices slumped following news of increases in supply by several key producers.
U.S. crude prices were down 3.0 percent at $42.89 a barrel.
Suncor Energy fell 2.6 percent to C$37.97 and Canadian Natural Resources declined 1.9 percent to C$36.88.
Bank shares, which had rallied on Monday, also lost ground. Toronto-Dominion Bank fell 0.6 percent to C$65.09, while the overall financial services group fell 0.3 percent.
Shares of Home Capital Group Inc climbed 4.6 percent to C$15.47 after the alternative lender said it would sell a portfolio of commercial mortgage assets valued at C$1.2 billion to private equity firm KingSett Capital.
At 11:37 a.m. ET (1537 GMT), the Toronto Stock Exchange's S&P/TSX composite index fell 103.47 points, or 0.68 percent, to 15,162.57.
Seven of the index's 10 main groups were lower. Industrials fell 0.5 percent as railroad stocks lost ground, while the materials group, which includes precious and base metals miners and fertilizer companies, also declined 0.5 percent.
Gold futures fell 0.3 percent to $1,240.7 an ounce as the U.S. dollar climbed and copper prices declined 1.3 percent to $5,651 a tonne.
Plane and train manufacturer Bombardier Inc has signed a $1.14 billion contract to supply passenger trains to the two new operators of Britain's South Western rail franchise. But the company's shares were unchanged at C$2.59.
Canadian wholesale trade rose more than expected in April, led by the machinery industry, data from Statistics Canada showed. The 1.0 percent increase topped economists' estimates for a gain of 0.5 percent. (Editing by Bernadette Baum)