Since it’s the end of the year, I’d like to share with readers my wish for 2020 — a productive economic bubble.

That may sound like an oxymoron, in part because bubbles don’t seem productive but also because I’ve railed against so many of them — from the 2008 US housing bubble to ballooning corporate debt, to what looks like a high-tech “ unicorn” bubble today.

But recently, venture capitalist and Cambridge university economist William Janeway reminded me that not all bubbles are created alike. As he lays out in Doing Capitalism in the Innovation Economy, there are both productive and unproductive bubbles. The latter category would include the speculative real estate bubble that unpinned the 2008 financial crisis, as well as today’s cryptocurrency bubble. Unproductive bubbles destroy value, especially when spread via the banking system, and they don’t leave much of use in their wake.