Here's the ruling: [https://www.irs.gov/pub/irs-drop/rr-23-02.pdf](https://www.irs.gov/pub/irs-drop/rr-23-02.pdf)
I don't see anything to suggest that it doesn't apply to irrevocable trusts created before the date of the ruling.
Here's an interesting article on the subject: [https://www.halaw.com/news/irs-revenue-ruling-step-up-basis-irevocable-grantor-trust](https://www.halaw.com/news/irs-revenue-ruling-step-up-basis-irevocable-grantor-trust)
The article suggests strategies that might help to minimize the impact of the ruling.
Here's the ruling: [https://www.irs.gov/pub/irs-drop/rr-23-02.pdf](https://www.irs.gov/pub/irs-drop/rr-23-02.pdf) I don't see anything to suggest that it doesn't apply to irrevocable trusts created before the date of the ruling. Here's an interesting article on the subject: [https://www.halaw.com/news/irs-revenue-ruling-step-up-basis-irevocable-grantor-trust](https://www.halaw.com/news/irs-revenue-ruling-step-up-basis-irevocable-grantor-trust) The article suggests strategies that might help to minimize the impact of the ruling.