What are the tax benefits for
Act 60, Puerto Rico?

A few points of clarification:

1. Understanding the ins and outs of bonafide residency and the key dates associated with it are critical to your relocation and tax strategy. In the example of a stock, which is taxed as personal property and thus a capital gain, the date that establishes your tax basis is the date in which you commence becoming a bonafide resident; this is also known as your move date, or the date in which you cease to have a tax home in the US. For Act 60 to kick in, you must successfully obtain your tax decree and satisfy the bonafide residency requirements for that calendar year (i.e. become a bonafide resident). If you do not accomplish these steps in full, all income will be taxed in the US (more on this in the next section).
2. Dividends and interest (benefits 1 and 2 above) are not considered capital gains, but rather “investment income”, because the return is not reliant on the initial capital expenditure. For investment income, the IRS considers the source of income to be where the payer, or company, is located. Therefore, unless the payer is based in Puerto Rico, you will owe US taxes on investment income even after moving to Puerto Rico