As one of the wealth managers dealing with UK-US individuals, let me reply on the question of when to hire one.
- Interview wealth managers when you have more than $250k iin investible assets, UK and US including money purchase pensions, excluding houses
- Hire one when you want help in making decisions on (a) asset allocation worldwide, and (b) how to use US pensions while in the UK to maximise the peculair tax advantage of cross border pensions (c) you want assistance in becoming financially independent quickly and effectively and then depleting it. (d) you want to review the brokers that will offer a valuation and dealing service for all your assets UK and US. Before you ask me for details, I'm preparing a brief in PDF, I'll let you know when it's ready
- don't hire one if you're a DIYer. 'Nun' is right that a DIY-er type person will get benefit from a wealth manager only for investment/asset management security selection research. But only 20% of people are DIY-ers. 30% seek control but to validate their planning choices: and 50% are delegators. As it happens my own firm does not offer a service to the delegators because as nun says the fees become so expensive that you have to wonder if the client is better off staying on deposit or in property. But for the rest, one can usually reduce financial service fees by half. I can name some UK US wealth management firms that do take 'delegators'.
- Ask which fiduciary standard they work to. Every wealth manager working under a fiduciary standard will undertake an exercise to ensure the service they have in mind is of value to the client before commencing work and this is extra to the requirement to ensure one can deliver what the client is requesting. So you'd expect a wealth manager to refuse to take you on if they're not actually convinced the result will be to your benefit. But some 'wealth managers' do not work to a high enough fiduciary standard, taking the view that their job is to sell 'approrpriate' products, so you have to ask ' what standard do you work to?'
I think there are four London-based wealth management firms currently offering specialist know-how of value to UK-US persons. Your CPA will know who they are, or you can ask me.