If you're still wondering, I run Active Trader using CrossOver Pro. The newest version 11.2 works with Mountain Lion. It does take some set-up to get it working, I believe I set Active Trader up using the presets for one of the other U.S. trading platforms that are listed in the CrossOver compatible apps list. Try a few different ones until one works.

Of course, you could always just dual-boot Windows and/or use Parallels to have a full copy of Windows with Active Trader. I chose not to do that because I don't want a bloated, crappy OS installed on my Mac. :-)

By the way, if you're only trading U.S. equities, you could use TD's new Thinkorswim platform. It's available for Canadians now, but only works with U.S. dollar accounts, and has no access to the TSX/TSX Venture. Thinkorswim is Java-based, so it runs just fine on either Mac/Windows.

Does anyone have experience trying to run Active Trader from TD waterhouse on Lion OS? The more basic version of the trading platform - TDWaterhouse, is completely Web Based. Apparently this new more advanced trading platform requires a download.