The new rules will see policymakers no longer be allowed to invest in individual stocks or bonds but only in "broadly diversified" funds and will have to hold those investments for at least a year (previously a month). According to the ECB:
"Under the enhanced rules, high-level ECB officials must limit their investments to publicly listed, broadly diversified collective investment schemes such as exchange-traded funds and mutual funds. A collective investment scheme is considered broadly diversified if it is not concentrated in a specific sector. Asset classes that are already held and that, following the amendments, do not fall into this category may be kept as legacy assets. This means that no further purchases of these assets are allowed and that any sales of such assets would require the prior approval of the ECB’s Ethics Committee."
The change is said to mitigate the risks of "misuse of confidential information and possible conflicts of interest" and will go into effect on 1 January 2023. I'm sure this is in part also triggered by the Fed fiasco in which we saw Kaplan and Rosengren resign last year.
In any case, if ECB policymakers are as bad about their investment picks as they are about the outlook on the economy, this will probably be better for all parties involved.