NOVELTY - A hydrocarbon composition comprises a hydrocarbon, and a conductivity improver.    USE - As hydrocarbon composition e.g. fuel oil, diesel, gasoline, biofuel, marine fuel, bunker fuel and heating oil; middle distillate oil and heavy fuel oil; and GTL (gas-to-liquid), CTL (coal-to-liquid), BTL (biomass-to-liquid) and/or OTL (oil sands-to-liquid) (claimed).    ADVANTAGE - The conductivity improver acts both as a conductivity improver and as anti-separation agent in the hydrocarbon composition; and it enhances hydrocarbon stability reserve, and combustion, by metering into a hydrocarbon composition. The hydrocarbon composition has a separability number which is less than the separability number of the hydrocarbon, and has improved combustion as measured by fuel economy, power, emissions, maintenance costs or maintenance intervals, compared to the hydrocarbon alone. The hydrocarbon composition exhibits good stability and good combustion performance. The conductivity improver reduces problems relating to sludge formation, filter blocking or inhomogeneity; and it increases fuel economy, increases power, reduces smoke, reduces emissions, reduces maintenance costs or increases maintenance intervals; reduces carbon content of exhaust fumes, reduces carbon deposition on part of the combustion apparatus or on parts downstream from it, such as exhaust ducting and heat recovery equipment; and reduces the formation of ash.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for an additive composition for addition to a hydrocarbon composition comprising: i) a conductivity improver effective as an anti-separation agent in a hydrocarbon composition; and, at least one of ii) a combustion improver selected from: iia) a metal compound selected from an iron compound, a manganese compound, a calcium compound, and/or a cerium compound, and/or iib) an organic compound selected from a bicyclic monoterpene, a substituted bicyclic monoterpene, adamantane, an optionally substituted bicyclic tetraterpene, and/or propylene carbonate; and iii) a dedicated asphaltene dispersant compound.