Mandatory Convertible

What Does Mandatory Convertible Mean?
A type of convertible bond that has a required conversion or redemption feature. Either on or before a contractual conversion date, the holder must convert the mandatory convertible into the underlying common stock.

These securities provide investors with higher yields to compensate holders for the mandatory conversion structure.

Investopedia explains Mandatory Convertible
These are often used when a traditional equity issuance would otherwise place severe market pressure on the underlying stock.