As a former UK employee of a US based company, I have accumulated a 401K account worth $40K. I never lived and worked in the US, so I don't have a SSN.
I understand I can avoid a 10% withdrawal penalty by leaving the money where it is until I reach age 59 & 1/2 in September 2014. Beyond that point, what is the most tax efficient way to withdraw the funds? Will I need to get a ITIN? I have seen conflicting reports on whether I will need to complete a W8BEN?

Any advice gratefully received.

Neil Matthews,
Cambridge, UK

Eventually, you WILL need an ITIN, but that can be applied for when you file your first non-resident tax return.

Once you hit the 59.5 years of age point, you can examine the tax rates in effect at that time to determine what is the best way to withdraw the funds.