The Financial Conduct Authority (FCA) in the UK recently voiced concerns about overseas advisory firms advising clients to transfer UK pensions into a self-invested personal pension using an offshore investment bond as they may be exposed to high and/or unnecessary charges.
 
This essentially means money is being invested with a third party Life Insurance company and the firms advising on these assets are receiving high commissions in return – to the detriment of your pension fund. It can also be very difficult (and expensive) to leave such arrangements once one has entered into them.