FYI, this is the answer I received from IB :
"Thank you for your inquiry.
At this time we can’t provide a definitive answer. I’ve consulted with my manager and most probably we will apply the same restrictions that were set forth with PRIIPs regarding investments in ETF, ETNs and Mutual funds for EEA (European Economic Area) based clients. That means that all clients will be regarded as Retail and won’t be able to make investments in US based ETFs, ETNs or Mutual funds that don’t provide the required documentation by the regulators. We will also offer the possibility to request to be reclassified as professional, most probably with the same requirements for PRIIPs.
The client would need to meet at least two out of the three criteria’s:
1 -I have: - carried out transactions, in significant size (i.e. value of trades totaling EUR200,000 or more) on the relevant market at an average frequency of 10 per quarter over the previous 4 quarters; and - at least EUR50,000 account equity at present.
2 - The size of the financial instrument portfolio in this account, defined as including cash deposits and financial instruments, exceeds EUR 500,000.
3 - I work or have worked in the financial sector for at least one year in a professional position, which requires knowledge of the transaction or services envisaged. "