Retirement planning for US-EU expats - best use of cash and citizenship options

[trying_to_make_it]

Hi EF!

TL;DR financial planning strategy for US-EU expats, how to address constraints related to citizenship

we’re both 40, married, EU citizens, US residents (green card), family of 4, double income, young kids with dual citizenship.

$2M net worth, as follows:

• half in net USD assets:
  • 15% cash and high yield savings @ 2%
  • 30% lazy portfolio (target funds, ETFs) in 401(k)’s and taxable accounts
  • 80% primary residence
  • -25% mortgage debt @ 3.9%
• half in EUR assets:
  • 50% in cash @ 0.1%
  • 50% in stocks (not well diversified, mostly one European blue chip)

After all expenses, interest and taxes, our total income allows us to save/invest about $230k per year, which goes primarily to our mortgage repayment and broad target funds / index ETFs, maxing out 401(k)’s.

No income (other than dividends) nor expenses in EUR.

Because we’re US persons, none of our financial institutions in Europe let us buy any securities hence rebalancing our portfolio isn’t possible (unless you tell me otherwise)

Our preferred retirement scenario is moving to Europe in 7 or 8 years and retire there in 15 years, but who knows what we'll end up doing

• what is the best use of our cash in EUR? Should we buy USD, pay off mortgage, further diversify our USD investments? EUR is quite weak against USD now so it doesn’t feel like the best move, but the cash doesn’t earn anything today. Or any idea how we could find investment opportunities in EUR?
• should we apply for US citizenship before leaving the country in a few years? pros: more flexibility with residency options, no exit tax when we leave, similar situation as our kids. cons: having to deal with IRS forever, US citizens in EU are drastically limited with investment options. Should just one of us become dual citizen rather than both?

thanks all!