> Readers should also note that, unlike the 2018 and the 2021 convertibles, where the principal is always repayable in cash, the 2019 convertibles may be redeemed wholly in shares (at Tesla's option and if the requisite conversion ratio has been met).

So yes the bond holder can choose to convert after Dec 1st 2018 and Tesla can force them to convert when the bonds come due in March 2019