Only retail electricity licensees (electricity retailers) are authorised to retail electricity to contestable consumers.

There are two types of electricity retailers: market participant retailers (MPRs) and non-market participant retailers (NMPRs).

MPRs have to be registered with the Energy Market Company (EMC) to purchase electricity from the National Electricity Market of Singapore (NEMS) to sell to contestable consumers.

NMPRs need not register with EMC to participate in the NEMS, since they will purchase electricity indirectly from the NEMS through the Market Support Services Licensee (MSSL).