A market trend is a putative tendency of a financial market to move in a particular direction over time. These trends are classified as secular for long time frames, primary for medium time frames, and secondary for short time frames. Traders identify market trends using technical analysis, a framework which characterizes market trends as a predictable price tendencies within the market when price reaches support and resistance levels, varying over time.
The terms bull market and bear market describe upward and downward market trends, respectively, and can be used to describe either the market as a whole or specific sectors and securities.
A primary trend has broad support throughout the entire market (most sectors) and lasts for a year or more.
A bull market is associated with increasing investor confidence, and increased investing in anticipation of future price increases (capital gains). A bullish trend in the stock market often begins before the general economy shows clear signs of recovery.
A bear market is a general decline in the stock market over a period of time. It is a transition from high investor optimism to widespread investor fear and pessimism. According to The Vanguard Group, "While there’s no agreed-upon definition of a bear market, one generally accepted measure is a price decline of 20% or more over at least a two-month period."
A market top (or market high) is usually not a dramatic event. The market has simply reached the highest point that it will, for some time (usually a few years). It is retroactively defined as market participants are not aware of it as it happens. A decline then follows, usually gradually at first and later with more rapidity. William J. O'Neil and company report that since the 1950s a market top is characterized by three to five distribution days in a major market index occurring within a relatively short period of time. Distribution is a decline in price with higher volume than the preceding session.
A market bottom is a trend reversal, the end of a market downturn, and precedes the beginning of an upward moving trend (bull market).
It is very difficult to identify a bottom (referred to by investors as "bottom picking") while it is occurring. The upturn following a decline is often short-lived and prices might resume their decline. This would bring a loss for the investor who purchased stock(s) during a misperceived or "false" market bottom.
Baron Rothschild is said to have advised that the best time to buy is when there is "blood in the streets", i.e., when the markets have fallen drastically and investor sentiment is extremely negative