A Self Invested Personal Pension (SIPP) is a type of personal pension plan.  It works in the same way with regards contributions, tax relief, eligibility are concerned.  However the main difference is that the SIPP has a more flexible approach to investments.

A conventional personal pension generally involves the plan holder paying money to an insurance company for investment in an insurance policy.  This means the money is invested with relatively little choice or freedom from the plan holder.

A SIPP allows the plan holder much greater freedom in what to invest in and for the plan to hold these investments directly.  The plan holder can have control over the investment strategy or can appoint a fund manager or stockbroker to manage the investments.

For SIPP contracts written under trust, the trustee controls the investment under instruction from the member.  It is possible for the plan holder to be the trustee.  If this is the case, an approved administrator must be appointed to carry out investment transactions.