Here's a tip British investors can't afford not to know about. Stocks and shares is a fancy name for a totally legal tax haven for your money. Every UK adult is allowed to save or invest up to £20,000 per year into tax-free ISER accounts.Most people have heard of cash ISERS. You won't pay any tax on savings interest, but building wealth over the long term using stocks and shares IS offers far more substantial tax savings. So imagine you'd invested £20,000 into a global index fund in your stocks and shares I ...