Many Olim Chadashim and 1st time residents, has to keep on filling tax returns in their country of origin which is also the main place where they keep doing business at (there sit their clients, suppliers, advisors etc.).
For example, Ole Chadash from the US who has a running business that was established there (LLC or s-corp) prior to the Aliyah, keeps on filling tax returns (1040) in the US since he/she would still consider a citizen (although not a resident).
This Ole, would probably mistakenly think, that if the business was established in the US prior the Aliyah, then he should keep on paying taxes to the IRS and the US government even if he doesn’t live there anymore.
Even if he goes to the US from time to time for work, it still doesn’t mean that the US has the first right to tax the business.
Here comes the tax treaty between 2 countries, that determines which country has the first taxation right – the country of the income’s source, or the country of residency.
Usually when it comes to incomes from business, the basic rule says, that if the business owner spends less than 183 days during the tax year in the country of the income’s source (the US in the example above), then the right to tax his business income is actually the country of residency and not origin.
Another familiar situation is someone how made Aliyah / returned to IL after 10 years at least abroad, and gets paid by a foreign company when living in IL.
If this person spends less than 6 months abroad (US), the Israeli Tax Authority would have the right to tax him and not the IRS.
The ITA might even ask for his taxes regardless of the fact he already paid them to the IRS and most probably won’t allow a forigen tax credit in this case (then this person would have to pay to the IL authorities and ask for a correction of his filling in the country of origin).
This would definitely be considered as a tax accident one should try to avoid.