Should I use "for" or "of" in the below sentence?
Your main reasons of/for this new business arrangement structure are for asset protection, it allows you to distribute income to your family members, etc.
Hello, Tony—I agree with Gustavo's response above, and would just like to point out that your sentence is a run-on. A new sentence begins at "it allows you . . .," but you have that part punctuated as if it were part of the preceding sentence.
If you want them to be part of the same sentence, you could change "it allows you to" to "allowing you to" (with some other changes): "This new business structure helps you mainly with asset protection, allowing you to . . . .".