It’s kind of debt, and kind of equity. It’s been around for decades, but has recently come back into fashion.

What is it? It’s convertible debt.

Convertible bonds are a clubby and often overlooked corner of the corporate finance world. Last year, plunging equity valuations made for some notable horror stories — like Peloton, Ocado and Affirm — but in recent months the market has become popular once again.

For this week’s episode of Cloud 9fin, our US managing editor Will Caiger-Smith sat down with David Hulme of Advent Capital Management (whose president, Tracy Maitland, wrote a book on converts) to get the lowdown on the asset class’s resurgence.