For easy access to Warsaw's central business district, the Warsaw Sheraton Plaza centre is hard to beat. The centre is part of the up-market Sheraton Plaza Hotel. It is surrounded by government and financial institutions such as the Warsaw Stock Exchange, considered the largest stock market in the region. Many service-related companies operate in the business district, and the city is also a magnet for young and promising companies - the number of small to medium-sized businesses has steadily increased, thanks to active encouragement and support from the city. In all, more than half a million companies operate in Warsaw and the surrounding areas. The Polish capital the biggest concentration of electronics and hi-tech industry in the country and has a rapidly expanding food-processing industry. Despite the city's rapidly growing service sector, traditional industries operate in the area, including a large steel mill and a tractor manufacturer.