It's not that they are all 'not living there'. They might live there, or have a family member/student live there, or their wife/kids while they stay in China.

It's not that they are all 'not living there'. They might live there, or have a family member/student live there, or their wife/kids while they stay in China. These people might be a little 'price inelastic' but also 'not stupid'. A 15% advantage for local buyers gives some leverage. It could also just be a little skittishness - 'what will the tax be next year'? Or 'will this cause other buyers to be skittish because if that happens, prices will drop, so I'll hold off'. 15% will definitely pull out a chunk of buyers - that pull out might be enough to make those buying 'at any price' not enough to keep the bubble up. Finally - Toronto saw a big increase after Van put in the law. The money just may have switched gears into TO.