Our company (our own niche brand of leather goods, currently with a limited company in Hong Kong) will initially sell online only. Most customers will be in the US, although we will accept international orders. In a couple years we hope to sell wholesale to brick and mortar stores around the world. Our objective is to reduce our tax burden, and we understand that non-US sales are taxed quite highly in the US. We also understand that HK companies without any operations in HK are not subject to income tax. We suspect it's best to have a Hong Kong parent company with a US child company. The Hong Kong parent company would be linked to all of our sales (online and non-US offline) EXCEPT our US offline sales, which will be under the US child company. The two country structure would make it easier for the smaller business customers in the US and also let us not get taxed outrageously on the non-US sales. Would appreciate any advice on this topic!
Non-US profits are generally taxed only if the cash is repatriated back into the United States. So, for example, Coca-Cola's profits that it generates in countries outside the United States are not taxed by the IRS until that cash is moved into an account that is domiciled in the US. Of course, this gets very complicated very quickly, isn't necessarily appropriate for an early-stage startup, and is the kind of thing for which you need to have accountants and tax attorneys on retainer or in-house to properly advise you.
Base your company on Ireland. This is the "cheapest" way to do it without having problems with the IRS (US tax organization).
If you want to go for 0% you can always go to a "tax heaven"and do what is called as trading. Bahamas, Panama, Virgin Islands, Jersey (france) are some examples.