Support/Resistance

  Support and resistance represent key junctures where the forces of supply and demand meet. In the financial markets, prices are driven by excessive supply (down) and demand (up). Supply is synonymous with bearish, bears and selling. Demand is synonymous with bullish, bulls and buying. As demand increases, prices advance and as supply increases, prices decline. When supply and demand are equal, prices move sideways as bulls and bears fight it out for control.

  Support is the price level at which demand is thought to be strong enough to prevent the price from declining further. The logic dictates that as the price declines towards support and gets cheaper, buyers become more inclined to buy and sellers become less inclined to sell. By the time the price reaches the support level, it is believed that demand will overcome supply and prevent the price from falling below support.

  One of the most-common and best-known trading strategies is this: "Buy at the support level and sell at the resistance level." The significance of the support level can be understood this way: Imagine that on a given day, for some particular reason (or by sheer chance) a stock is traded very heavily at a certain price level. Also imagine that many traders remember this price level because they bought or sold the stock at this level. Next, suppose that the stock price first moves up away from this level and, later on, (for some reason or no reason) the stock price trades back again to the earlier level.
Traders who previously bought the stock and sold it for a profit would likely buy it again at this level. Those who previously sold the stock at this level and missed the recent run-up would have a chance to buy it back. Such buying activities usually slow down the drop and may reverse the momentum.
 

  At least, the stock price may take a rest at this level before moving in a new direction. We can then say that the stock price has hit some "support level," by which we suppose that it most likely will not quickly drop through it. The sensible trading strategy is, of course, to buy the stock near this support level, monitor it closely, and sell it to cut losses if it falls meaningfully lower than the support level. If the support level does prevent the stock price from falling and it starts to bounce back, the trader can make a nice profit that is usually much larger (!) than the amount of loss incurred if the trade turned south and loss had to be cut.