On the Massachusetts income tax Form 1, line 5 is for "Interest from Massachusetts Banks". This interest income gets an amount deducted from it ($200 for married filing jointly), and is reported there on the main tax form. Whereas interest from any other sources gets reported separately over on Form 1 Schedule B.
So certainly if I have a savings account with my brick & mortar bank down the street, and get interest from it, the interest from it would be this "Interest from Massachusetts Banks" and get this deduction. But what about if I use a brokerage account (like Fidelity), and purchase a brokered CD that is from a Massachusetts bank? There's a sense in which it's Fidelity paying me the interest (in that they're the ones who would be sending me the 1099-INT), and Fidelity isn't a Massachusetts Bank, but there's also a sense in which they are just passing along what is truly just interest that is being paid me via a Massachusetts Bank.
So for this interest from a brokered CD that's ultimately from a Massachusetts Bank, do I report it on Form 1 Line 5a or does it only show up on Form 1 Schedule B?
The Form 1 instructions don't really clarify beyond saying that Line 5 is for interest from deposit accounts (like CDs) "in Massachusetts banks", and doesn't clarify whether getting them indirectly through a brokerage counts.