I hold a mixture of UK shares and US funds/ITs in a Fidelity ISA - I'm keen to transfer this to IG as wider range of stock and share markets available but I don't know whether I can hold ITs/Funds within an IG stocks and shares ISA. Will I need to sell my IT/fund holdings and hold them as cash in my Fidelity ISA prior to requesting the ISA transfer to IG?
You should be able to transfer them without selling them. I’ve done this with other brokers in the past. The only problem is that there will be a period in which you can’t sell the holdings if the prices hit notional stop losses you might have.