Trendline
A trendline is a straight line drawn on a price chart connecting a series of successive highs or lows to visually represent the direction and pace of a price trend. Trendlines on Nifty 50 and Bank Nifty charts have been used historically to identify the slope and boundaries of prevailing trends.
An upward trendline is drawn by connecting two or more successive higher lows — each pullback low higher than the previous one — creating a rising support line. A downward trendline connects two or more successive lower highs — each rally high lower than the previous one — creating a declining resistance line. The validity of a trendline is generally considered stronger when price has touched it on multiple occasions without breaking through.
On long-term Nifty 50 charts, multi-year upward trendlines connecting major bull market correction lows were drawn and widely referenced. The trendline connecting Nifty's 2009 post-crisis low, the 2011 correction low, and subsequent pullback lows during the 2014–2019 bull market was cited by technical analysts as representing the structural support of the long-term uptrend. When Nifty breached this line during the COVID-19 crash in March 2020, it was noted as a significant technical development before the subsequent rapid recovery.
The subjectivity of trendline drawing is a well-known limitation. Different analysts drawing trendlines on the same chart will often produce slightly different lines, each claimed to be valid. The choice of which lows to connect, whether to use intraday wicks or closing prices, and the time period under analysis all affect the trendline's placement and slope. This inherent subjectivity means trendlines are analytical tools for discussion and context-setting rather than objective, data-derived indicators.
Channel lines — parallel lines drawn above and below a trendline to encompass the typical price range within a trend — extended the trendline concept to identify both the support boundary and the resistance boundary of a trending move. Nifty trading within a rising channel for extended periods was documented by technical analysts, who noted when price approached either boundary as potentially significant from a historical pattern perspective.
A common error is treating trendline breaks as highly reliable reversal signals. Trendlines are broken regularly without producing meaningful reversals, particularly during temporary volatility spikes or news-driven intraday moves. False trendline breaks followed by recovery above the line were observed frequently on NSE, demonstrating that a single trendline break requires confirmation from other indicators before drawing conclusions about trend change.