I wonder how much (if any) of their cash is invested in Tesla convertible debt? Apple has been bumping up their R&D spend (not even including their acquisitions

I wonder how much (if any) of their cash is invested in Tesla convertible debt? Apple has been bumping up their R&D spend (not even including their acquisitions) by 20% or more annually for quite a few years: it's now up to around 5% of revenue (hard to calculate exactly, given the seasonality of their revenue). So far they've created at least 4 absolute breakthrough products, 4 more than most Fortune 500 companies ever achieve, including the most successful product ever (1.2 billion sold).