Hi there,
There is an entire application process for a company to 'graduate' to the TSX Index. Each company will have its own unique set of circumstances and there is no prescribed process that results in automatic graduation. It is up to each company to decide when to apply for a TSX Listing.
Although it does add a sense of legitimacy and increased interest from investors - stock price will move on fundamentals. Simply listing on the TSX will have no effect outside of the fact that it could be added to funds that track certain indexes. This could lead to increased liquidity and perhaps, a short term increase in price due to buying pressure.
Bottom line - if you are interested in a company on the TSX Venture today - no sense in waiting for it to trade on the TSX.
Mat