Thank you very much @dmertz,
I think people in this discussion forum obtained lots of useful information.
One more question - an irrevocable trust has 5 beneficiaries. In 2021, the trustee distributed DNI to only one beneficiary. In this case, should the beneficiary who received DNI pays income taxes, or should all beneficiaries pay a portion (20% each) even if only one of them received in 2021? I'm pretty positive that the beneficiary who received DNI should pay income taxes, but not 100% sure since I can't find IRS provision or Rev Rul. People might ask why only the received party pays income taxes even if DNI is for all beneficiaries. Many thanks for your contribution and time spent on this.
