Bulgarian state-owned electricity company NEK and Electricity System Operator 
(ESO) completed on February 4 the last phase of their split-up, regarding the 
unbundling of the ownership of the network and the associated assets, the 
Bulgarian Energy Holding (BEH) said on Wednesday.
The unbundling will 
allow ESO, as the owner of the grid, to start the process of its certification 
as an independent transmission operator as a further step in the development of 
a competitive and financially stable energy market, BEH said in a press 
release.
The split-up of the two companies is required under the EU’s 
Third Energy Liberalisation Package.
Bulgarian Energy Holding (BEH) - a 
state-owned holding company set up in 2008 which controls Mini Maritza-Iztok, 
NEK, ESO, Bulgargaz and the country’s sole nuclear power plant Kozloduy - took 
full control of ESO from NEK in 2013.