My partner does not have to pay tax because he is not a permanent resident or citizen. If that's the case, you do not have to file a tax return or pay income tax. You only have to pay sales tax if your purchase something, and even some states will return your sales tax. Logic says that if you do not have to file a tax return, then what taxes would you have to pay in rental income?
The crucial difference here appears to be the one between active (trade or business income) and passive income. Your nonresident partner does not have to pay taxes on the active income he receives via the "pass through" feature of the LLC.
According to the information in the "quote" below, passive income earned in the USA by nonresidents is subject to a 30% tax even though they are not required to file a tax return.
Passive income includes dividends as well as interest received on money deposited in a US bank
, royalty, rents, alimony, certain capital gains, and 85% of U.S. social security benefits
Even if it turns out the rental income for the apartment in Argentina is not subject to taxation in the US (because it is located outside of the US), the US bank in which the rental income is deposited would be required to withhold 30% of interest paid to the foreign account holder and send it to the IRS, even though the account holder is not required to file a tax return.
The unanswered questions are still, "If the rental income is received by a business in the US and then deposited into the nonresident's US bank account, is it subject to the 30% tax?" and if it is, "Is the rental agency responsible for withholding the 30% tax and sending it to the IRS?"
Based on what I've read, if the apartment was in the US the rental income would be subject to the 30% tax, but
If you are a nonresident taxpayer and your only U.S. source income consists of passive income, (and) you are not required to file a U.S. tax return, how do you pay the 30% tax due on rents, alimony, certain capital gains, and 85% of U.S. social security benefits?
Passive Income
Unlike trade or business income, U.S. source passive income is taxed on a gross basis at a flat tax rate of 30%. “Gross basis” means that no deductions or exemptions are allowed against this income. For purposes of this discussion, the most typical types of income which fall into the “Passive Income” category are interest,dividends, royalty, rents, alimony, certain capital gains, and 85% of U.S. social security benefits
The flat tax of 30% is usually collected through a withholding mechanism with the burden to withhold placed upon the payor of the income.
For example, a U.S. corporation is generally required to withhold the 30% tax from any dividends it pays to nonresident taxpayers, and remit this withholding to the U.S. government on behalf of the individual.
If you are a nonresident taxpayer and your only U.S. source income consists of passive income, you are not required to file a U.S. tax return.
The withholding tax generally satisfies any U.S. tax liability.
Source: http://www.gtn.com/U...als.pdf (pages 29 and 30)