I am working on the Illinois annual tax return for my S corporation. And it indicates that " If you are making the business income election to treat all nonbusiness income as business income, check the box and write 0 on Line 36 and 44". And in the instruction, it says that the decision is irrevocable.
The problem for me is that I don't know what type of income falls into the category of nonbusiness income. And I don't know what are the pros and cons for treating it as "business income". Any insightful advice on that is high appreciated.
Another question is that I have originally put some money in the business as start up costs/investment. Now it looks like I need to infuse some more cash in it (5-10k). Is it better to treat that as a loan or an investment from tax point of view? Thanks much in advance.