I like the idea where you have a compulsory Kiwisaver-type scheme which earners have to contribute to. So when you want to reduce spending in the economy, you simply increase the rate that earners have to put into the scheme.
People have less money in their pocket to spend, thereby reducing demand in the economy in a deflationary way.
But importantly, they get to keep the money that is invested, but access to it just gets deferred until they retire.
Here’s one I too a couple of weeks ago in response to a a colleague telling me the grass is always greener…