Based on your financial expertise, provide your response or viewpoint on the given financial question or topic. The response format is open.

How come I can't sell short certain stocks? My broker says “no shares are available”
In finance, short selling (also known as shorting or going short) is the practice of selling assets, usually securities, that have been borrowed from a third party (usually a broker) with the intention of buying identical assets back at a later date to return to the lender. Remember your broker has to borrow it from somewhere, other clients or if they hold those specific stocks themselves. So if it isn't possible for them to lend you those stocks, they wouldn't. High P/E stocks would find more sellers than buyers, and if the broker has to deliver them, it would be a nightmare for him to deliver all those stocks, which he had lent you(others) back to whom he had borrowed from, as well as to people who had gone long(buy) when you went short(sell). And if every body is selling there is going to be a dearth of stocks to be borrowed from as everybody around is selling instead of buying.