While living overseas, my wife, who is a UK citizen, briefly received contributions from her UK-based employer for a pension up until a few weeks prior to our marriage. The year of our marriage, I filed a joint return with her status specified as a non-resident alien, but only counting income she earned from our marriage date through the end of that year. We have since relocated to US and she is now a US resident. In 2019, she took full distribution of that foreign employer pension. Would (a) this distribution, be US taxable given its from a pension related to services she performed while in no way connected to US, and if so, (b) would the full distribution amount be taxable given she didn't have to make any contributions herself, and (c) how would we file this given no 1099-R was generated by the foreign employer? I saw this IRS guidance but am not sure if this applies in anyway:
Foreign Contributions while a Nonresident Alien
Your contributions and your employer's contributions are not part of your Cost if the contribution was based on compensation for services performed outside the United States while you were a nonresident alien and not subject to income tax under the laws of the United States or any foreign country (but only if the contribution would have been taxable if paid as cash compensation when the services were performed).
