(Updates throughout with fresh details, analyst comment, market moves)
* TSX up 18.93 points, or 0.13 points, at 15,127.05
* Six of the index's 10 main groups rise
By Solarina Ho
TORONTO, May 19 (Reuters) - Canada's main stock index climbed for the third straight session on Tuesday, as financial stocks helped lead the market higher and investor optimism got a boost from U.S. stocks closing at record highs on Monday.
Valeant Pharmaceuticals International Inc, a perennial index heavyweight, lead with a 2.7 percent rise to C$277.24. The overall healthcare group jumped 2.1 percent.
Financial institutions rounded out the top five most influential gainers, with Royal Bank of Canada up 1.1 percent at C$79.68. Manulife Financial Corp rose 1.8 percent to C$23.03. The overall group, which make up about a third of the index's weight, advanced 0.7 percent.
"There should be some follow through this week on New York hitting new highs, though it's going to be slow," said Douglas Davis, chief executive officer at Davis-Rea.
At 10:31 a.m. EDT (1431 GMT), the Toronto Stock Exchange's S&P/TSX composite index rose 18.93 points, or 0.13 points, at 15,127.05. Six of the index's 10 main groups were up.
The index traded in negative territory earlier in the session, dragged in part by energy stocks, hurt by softer oil prices.
Suncor Energy Inc was off 0.9 percent at C$36.25, while Cenovus Energy Inc fell 1.7 percent to C$20.44. The overall energy group gave back 1.5 percent.
Despite Tuesday's moves lower, Davis expressed some optimism for the sector, noting the firm has "done well with the recovery in energy and we don't think that's over."
Also tempering gains was a 0.6 percent loss by the materials group, home to mining and other resource companies. First Quantum Minerals Ltd lost 4.9 percent to C$17.91, while Cameco Corp tumbled 4.6 percent to C$19.74. Goldcorp Inc was down 1.5 percent at C$22.96. (Reporting by Solarina Ho; Editing by Marguerita Choy)