Change

Change represents the absolute difference between the current price and the previous close, measuring how much a security's price has moved during the trading session. This simple calculation shows the dollar (or currency) amount gained or lost per share since the market last closed, providing immediate context for understanding current price action.

The calculation:

Change = Current Price - Previous Close

Example:

Previous Close: $145.00
Current Price: $148.50
Change: +$3.50

Why change matters:

• Quick assessment: Immediate sense of today's movement
• P&L calculation: Shares owned × Change = Dollar gain/loss
• News reaction: Shows market response to overnight developments
• Real-time tracking: Updates throughout the trading day

Interpreting change:

• Positive change: Stock trading higher than yesterday's close
• Negative change: Stock trading lower than yesterday's close
• Zero change: Trading exactly at previous close (unchanged)

Change vs. percentage change:

• Dollar change: Useful for calculating actual P&L
• Percentage change: Better for comparing across different price levels
• Example: $5 change means different things for a $50 stock vs. $500 stock

Context considerations:

• Stock price level: Higher-priced stocks have larger dollar swings
• Typical range: Compare to average daily change for perspective
• Market context: Individual change relative to market movement
• Volume: Change on high volume is more significant

Limitations:

• Pre/post-market: Change during regular hours only; after-hours moves separately
• Gap effect: Gap at open included in change calculation
• Split adjustment: Must adjust for stock splits when comparing historical changes

Change appears on every stock quote and ticker, providing the most basic measure of daily performance. Use alongside percentage change for complete context on the significance of price movements.