Gap Up
When the market opens sharply above the previous close, leaving an empty price zone — and a critical decision point for traders.
Definition
A gap up occurs when a stock, index, or futures contract opens at a price that is meaningfully higher than the previous session's close, creating a visible blank zone on the price chart where no trading took place. This gap reflects an imbalance between supply and demand that accumulated while the market was closed — often driven by corporate announcements, global cues, or macroeconomic data released overnight. A gap up is distinct from a routine higher open; the opening price must exceed the prior session's high to leave a true unfilled gap on the chart.
Why it matters
Gap ups are particularly significant on the NSE and BSE because Indian markets are heavily influenced by US market closes, Asian trading sessions, and pre-market SGX Nifty futures. A large gap up in Nifty 50 or Bank Nifty at 9:15 AM immediately alters the risk landscape for option writers and positional traders. Gaps can act as launching pads for continued upward momentum — a breakout gap — or they can be quickly "filled" as early buyers take profits and sellers step in. Understanding which type of gap has formed determines the appropriate strategy. Rising open interest in call options combined with a gap up often signals institutional conviction in the move.
How it works
Gaps form because exchanges close but sentiment does not stop. Between sessions, news events, earnings results, FII/DII flows, and global market movements all reprice expectations. When the NSE opens and buyers vastly outnumber sellers at the prior closing price, the market jumps higher to find equilibrium. The gap on the chart represents prices at which no transaction occurred. Technicians classify gaps as common (fills quickly, low significance), breakaway (forms at the end of a consolidation), runaway/continuation (mid-trend, high momentum), or exhaustion (appears late in a trend and often reverses). A gap that remains unfilled over several sessions is generally considered stronger support.
Example
Suppose Infosys closes at a hypothetical Rs 1,500 on a Tuesday. That evening, the company announces quarterly earnings that beat estimates. On Wednesday, Infosys opens at Rs 1,560 — well above Tuesday's high of Rs 1,512 — leaving a gap between Rs 1,512 and Rs 1,560 on the daily chart. Traders who bought positionally before the result see strong unrealised gains. Short-term traders watch whether the price holds above Rs 1,560 for a continuation trade or whether it dips back to Rs 1,512 (gap fill) before deciding on direction.
Track gap moves with live data
TradePulse's option chain shows real-time open interest shifts that help confirm whether a gap up is likely to hold.