No one knows if IB will close NZ accounts. Prior to leaving Canada, Daytek was my US broker, then Ameritrade bought them out, then TD merged with them, then finally Charles Schwab bought them out. I don't think TDA had any intentions of closing foreign clients out until Schwab came along.
Have a look at IB's list of countries they accept clients from:
https://www.interactivebrokers.com/en/index.php?f=7021
Then compare that list to what other major brokers in the US are willing to accept? It's very clear IB is sitting on the other side of the fence as they disregard the CRS or foreign gov't regulations. Then there's the anti-$ laundering aspect. I wonder how many of those countries in that list have a thorough policy against laundering $ ? I recall Mexico claimed that status while El Chapo drug $ went into HSBC's bank accounts; "saying and doing are 2 different things".
Keep in mind, since the eruption of the Panama Papers (and similar tax free haven breaches that the media has exposed in the past several years), the OECD and UN has stepped up their tax evasion policy. This brought out the CRS, and recently, Janet Allen's meeting at the UN earlier in the year, to have a global minimum tax on corporations. We've seen the EU try to tax companies like Apple in Europe (despite being incorporated in Ireland where they negotiated a tax free status ; no different than the US auto-pac negotiates a free trade, duty free, tax free zone in Mexico. So the more appropriate question is how far will the sovereignty of a country remain credible if foreign gov't entities can muscle arm their policies?
Then there's the NZ side of things where I see brokers like Jarden and Macquarie milking in fees off clients in much the same way I saw brokers back in Canada do the same in the early 90s. What brought on change in Canada was competition from the US. Canada was forced to remove archaic regulations such as a managed fund had a minimum 33% domestic Cdn asset requirement. The Cdn gov't knew they could not stop people from wanting to invest in US equities nor structure tax laws to discourage investment from leaving Canada (as the US stakeholders had investment heavily tied into Canada). However when I look at NZ, we have a horse of a different colour. We're geographically remote from all the major equity markets. We have gov't FMA regulations that are telling foreign brokers not to deal with NZ residents. We have a tax structure that is vastly different to the taxation in most OECD nations (ie. we don't have a formal CGT policy). We have FIF that taxes paper gains. We have managed funds that tax under RWT vs N. America residents that do 'deferred taxation' in their investment RRSP/401K etc plans.
On different news. My partial ACAT transfer came through from TDA which took about 3 days. This means in the future months, a full account transfer can be done without any hitches if TDA has to be closed out.