There's no way to require foreign entities outside the US to file US tax paperwork, so you would not expect a foreign sale to result in a 1099-S. You are still required to report and pay capital gains tax following US tax law (assuming you are a US citizen, green card holder, or resident alien, which makes you subject to US tax law). If you also pay tax in the foreign country, you may be able to take a deduction or credit on your US tax return for the foreign taxes paid on the same income. Also, some countries may calculate capital gains using different rules, or have an inflation adjustment, but on your US return you will figure the gain and tax by US rules.
