How do I control the element of risk?
With discretionary or advisory services, this is the responsibility of the investment manager.
At the outset you will have agreed the degree of risk you feel comfortable with and your broker will manage your portfolio accordingly. You may be advised to spread your investments across a wide range of companies by investing in a unit trust, or you may wish to strike your own balance between riskier investments and reliable performers.
However, if you are an execution-only client, the assessment of risk on your investments is entirely down to you.