(Adds details, updates prices)
* TSX up 26.33 points, or 0.2 percent, at 13,523.40
* Seven of the TSX's 10 main groups rise
TORONTO, March 21 (Reuters) - Canada's main stock index rose on Monday as Valeant Pharmaceuticals International Inc's shares surged after the drugmaker added an activist investor to its board.
Valeant shares were up 12.3 percent at C$39.22 after Chief Executive Officer Michael Pearson stepped down and the company appointed William Ackman to its board.
It had traded at a peak nearing C$350 last August.
Other influential movers on the index included Bombardier Inc, which rose 3.9 percent to C$1.34 while awaiting a federal government decision on whether to invest in the struggling planemaker.
The Liberals on Tuesday will unveil their first budget since coming to power in October, having promised stimulus spending to boost economic growth.
At 10:13 a.m. EDT (1413 GMT), the Toronto Stock Exchange's S&P/TSX composite index was up 26.33 points, or 0.2 percent, at 13,523.40.
Seven of the index's 10 main groups were in positive territory, with only slightly more advancers than decliners overall.
The materials group, which includes precious and base metals miners and fertilizer companies, added 0.6 percent. Barrick Gold Corp advanced 1.7 percent to C$19.44.
The energy group barely rose, with oil prices stable after touching a 2016 high above $40 a barrel last week.
Enbridge Inc declined 1.5 percent to C$48.95.
The financials group slipped 0.1 percent, and industrials rose 0.3 percent. The healthcare sector, a five-member group including Valeant, jumped 4 percent. (Reporting by Alastair Sharp; Editing by Lisa Von Ahn)