It is not obvious in some analyses, but it is important to note that economic profits include opportunity costs. The profit of an entrepreneur (normal profit) is usually positive, but economic profit can be either positive or negative (loss). That's why the opportunity cost is included: in a completely competitive market, when marginal cost equals marginal revenue, profit maximization or loss minimization conditions arise. If the market price is lower than the total average cost, which means that the economic profit is negative, the entrepreneur needs to compare the value of the loss and the average variable cost. If the business continues to operate, the negative economic profit must not be lower than the average variable cost, otherwise the entrepreneur would rather shut down the company than continue to take the loss. British Glass is organising a one-day seminar on funding for decarbonisation and energy efficiency work on Thursday 2 November (north of England, venue TBC) – which will be attended by British Glass members’ and non-members. "We are concerned that if the UK decides to leave, it is likely to lead to a weaker pound, higher inflation, lower disposable income and less investment," she said.