do not trade first 20 minutes when market opens

 The recommendation to avoid trading during the first 15 to 30 minutes of the market open (9:30 AM – 10:00 AM ET) is a common "rule of thumb" used to protect traders from extreme, unpredictable volatility. While not an official regulation, many professionals suggest this window to allow the "opening rush" of orders to settle and for reliable technical patterns to form. 

Key Reasons to Wait

• Extreme Volatility: The first 20 minutes often see aggressive price swings as the market reacts to overnight news, earnings, and global events.
• Misleading Signals: Technical indicators (like VWAP or moving averages) require time to "settle" and can provide false signals in the first 15 minutes of price action.
• Wider Spreads: Liquidity can be thin immediately at the open, leading to wider bid-ask spreads and higher slippage, which increases the cost of entering a trade.
• The "10:00 AM Reversal": Many traders wait for the first 30 minutes to print on the chart because the market frequently course-corrects or reverses its initial trend right around 10:00 AM ET. 

Strategic Exceptions

While beginners are often advised to stay away, seasoned traders may use this period for specific high-risk strategies: 

• Opening Range Breakout (ORB): Traders mark the high and low of the first 15 or 30 minutes and enter a trade only when the price breaks out of that range.
• Scalping: Experienced scalpers may target the high volume of the first few minutes for quick, small profits, though this requires high-speed execution and strict discipline.
• Closing Positions: If you already hold a position, the high volume at the open can be an ideal time to sell into strength and lock in profits from an overnight move. 

Summary of Common "Wait Times"

Trader Profile	Suggested Wait Time	Purpose
Novice / Beginner	30 to 60 minutes	Avoid emotional trades and high-risk volatility.
Learning Trader	15 to 30 minutes	Wait for the "opening range" to establish a clear trend.
Experienced	0 to 15 minutes	Capitalize on high volume and momentum gaps.

For additional guidance on managing risk during volatile periods, you can review resources from Charles Schwab or Investopedia's beginner tips.