Had the phone call with MexTax, which seem very knowledgable. The information was quite enlightening in a sense and different than what I had understood previously.
When looking at taxes, you really need to decide and strategize on either setting up a Bank Trust (Fideicomiso) or a Corporation. It seems the most common recommended path is the Bank Trust. The general rule seems to be that if you only have one property, or possibly even two, its best to go with a Bank Trust for simplicity and because the rental income typically won't be that high and if you have multiple properties, then its worth to do the Corporation.
Apparently though its not the amount of properties, but more so the value and therefore the rental income.
According to MexTax, you will get taxed twice with a Bank Trust, but not with a Corporation. The way the taxes are paid is also much different between the two as well.
If you do a Bank Trust, then the STR platforms (Short Term Rental), say Airbnb in this example, will actually withhold the 16% VAT (sales tax for us Americans) plus 20% Income Tax (36% total) and they will send it off to the Mexican government. There is nothing else to file with the Mexican government, its simply and straight forward. You do however get sort of double taxed here. For example, say you rent out your condo for one night for $100.00 through Airbnb. $36.00 (36%) of that gets withheld by Airbnb and you get a net of $64.00 deposited into your US bank account. You now have to report this net of $64.00 as income, and that will no we taxed by the US. If you are saying paying taxes at 25%, your $64.00 ends up being $48.00 net. So out of your $100.00 you rented out the condo for, you end up with $48.00 and effectively paid 52% in taxes.
That's in contrast of how it works if you set up a Mexican Corporation. With a Mexican Corporation, you get issued an RFC, essentially like an EIN (or SSN) and now you pay taxes directly yourself to the Mexican government. Airbnb in this case would not withhold any of the $100.00, you could get the entire thing. You still have to pay 16% VAT and now you have to pay 30% in Income Tax to Mexico, however that can be offset by expenses. So if you have an HOA fee, or a management company, or you buy furniture for your rental, or repairs, that can all be deducted so your taxable income won't be the full $100.00, it may be $80.00, bringing down the effective tax rate. The BIG advantage here however is that due to a treaty between the US and Mexico, you can now use the taxes paid in Mexico as a credit on your US taxes owed. So if you rent out the condo for $100.00, and you pay $16.00 for VAT leaving a net of $84.00. You then pay the 30% Income Tax...not sure if the VAT is a deductible expense or not...I'm going to assume that it is, so you pay 30% on $84.00 leaving you with a net of $58.80, which means an effective tax rate of 41.2% vs 52% in the first example. Then when it comes to US taxes, say you owe $50.00 in US taxes...you already paid $41.20 in taxes to Mexico, so you only owe the US $8.80 additional and you would have paid a total $50.00 in taxes, which you would have paid anyway without the condo in Mexico since you owed the US $50.00 in taxes in the first place (from US income).
Hope all that makes sense. :)
The same apparently applies to Capital Gains Taxes. You only get credit on your US taxes if its set up as a Corporation in Mexico.
So then the question is why wouldn't everyone do the Corporation? Reason is, its a lot more expensive yearly and upfront in fees and there is a lot more involvement. This is where people say if you only have one rental, its not worth it. Its approx $2000.00 up front to set it up for the CPA firm and then about $1500 per year to file the required monthly and year end tax reports, etc. You have have to keep books and records of expenses and all of that in order to take the deductions off the taxable income.
If you rent something out and its relatively cheap, say $150/night average at 65% occupancy and your income is ~$35,500 per year, the savings in tax by setting up a Corporation may be offset by all the fees plus all the headaches. However if you have multiple properties, or an expensive beachfront property that rents for $750/night average with a 65% occupancy, you're looking at ~$178,000 in yearly income and the tax rate and not being double taxes will make a huge difference.
I am setting up another consultation with a CPA that specialized in international real estate to see how their services and pricing compares and will likely go the Corporation route with one of them.