MODEL AND METHODS
There are several large firms, dominate an industry
(oligopoly), that sell compost (phase III) in the compost market
in Poland. The barriers to entry are high, which makes it
difficult for firms to enter into the industry. Consequently,
long-run economic profits may be earned by firms in the
industry. The data relating to the financial performance of the
entities dealing in manufacture of mushroom compost (phase
III) in Poland2
were analyzed.