18 REDUCING MARKET DISTORTIONS FOR A MORE PROSPEROUS UKRAINE shareholder. That same oligarch controls an oil-transportation company and owns the country’s largest network of gas stations. These multi-market contacts facilitate explicit or tacit collusion. Most markets in Ukraine are highly concentrated, with the same 昀椀rm or 昀椀rms persistently com- manding large and stable market shares. Markets with a large SOE footprint that have not been subject to privatization have tended to retain their structure over time. This is particularly true in the electricity and gas production and import subsectors. Other markets, including air transportation and fertilizer production, remain concentrated even though they lack strong network e昀昀ects or other charac- teristics of natural monopolies. The enduring concentration of these normally contestable markets likely re昀氀ects uneven competitive playing 昀椀elds due to the preferential tax treatment of incumbents and/or unnecessarily high administrative barriers to entry, including restrictions on foreign investors (Figure 17). FIGURE 17 Market Concentration in Key Sectors with SOE and Oligarch Participation Market share of largest player (%) 100% Energy imports Dry eggsGas imports 80% Fertilizers Airlines Tomatoes Oil Energy extraction 60% Generation Airports Iron ore Mobile 40% Coal telecom Shell eggs Poultry 20% Pork Ports Milk Meat Grain Concentration Low Medium High index (HHI) (