Another item to add to your list would be a firm trying to maximize total revenue. I firm like Intel, which seems to have a corner on processor production, is still bound by the intention to maximize revenue. So if they limit production to raise prices, and earn a higher profit margin, investors will come knocking. They will want to invest in this firm that is laying golden eggs. But investors want to be rewarded. They want as high a return as possible. Just look at Henry Ford’s partners back when he was starting Ford Motor Company. So high yields will draw in the investors, and the only way to satisfy them will be to increase production and lower prices as a result, maximizing total revenue, increasing P/E ratio.