Understanding "Today's Return": Why Our Numbers May Differ From Financial Portals
An educational guide explaining the difference between 24-hour Close-to-Close returns (used by financial search engines) and Intraday Open-to-Close price action, overnight gaps, and real-time execution telemetry.
The Two Different Definitions of "Daily Return"
When monitoring a portfolio, investors frequently notice that a stock displayed on a quantitative trading dashboard may show a slight positive or negative divergence compared to general consumer finance portals (such as Google Finance or Yahoo Finance).
This difference is not an error—it is the result of two distinct mathematical methodologies used across the financial industry:
| Methodology | Mathematical Formula | What It Measures |
|---|---|---|
| 1. Standard Financial Portal Method (Close-to-Close) |
(Current Price - Yesterday's Close) / Yesterday's Close
|
Measures the total 24-hour price change from 4:00 PM ET yesterday to right now. This calculation incorporates the overnight gap created by pre-market earnings, macroeconomic announcements, and global overnight futures trading. |
| 2. Execution Session Drift (Open-to-Close) |
(Current Price - Today's Open) / Today's Open
|
Measures only the intraday movement during the active US regular market session (9:30 AM ET to 4:00 PM ET). It isolates how institutional market makers have traded the stock since the opening bell, completely filtering out overnight gap noise. |
An Illustrative Real-World Example: The "Gap Up and Drift Down"
To understand how a stock can be simultaneously reported as positive on one website and negative on another, consider a typical market scenario:
- Yesterday's Official Closing Price: $100.00
- Overnight News: Strong earnings or macroeconomic news hits overnight, causing the stock to gap up.
- Today's 9:30 AM Opening Bell: The stock opens at $103.00 (a +3.0% overnight gap).
- Today's 4:00 PM Closing Bell: Over the course of regular trading hours, traders take short-term profits. The stock settles at $101.50.
How the Two Systems Report This Exact Same Day:
• Consumer Financial Portal (Close-to-Close): Compares $101.50 to yesterday's $100.00 close: +1.50% Today.
• Intraday Session Drift (Open-to-Close): Compares $101.50 to the morning's $103.00 open: -1.46% Today.
Both numbers are mathematically correct. The portal is saying: "The stock is 1.5% higher than it was 24 hours ago." The intraday session metric is saying: "Since regular market trading opened this morning, price action drifted lower by 1.46%."
Other Common Factors Behind Price Discrepancies
Beyond the Close vs. Open formula, several technical factors cause price differences across platforms:
- Pre-Market & After-Hours Quotes: Outside regular trading hours (9:30 AM – 4:00 PM ET), some websites display extended-hours prints where thin liquidity can cause wild temporary price swings, while official strategy dashboards use confirmed consolidated regular-session prints.
- Delayed vs. Real-Time Feeds: Free retail websites typically display data delayed by 15 to 20 minutes (often marked with a small disclaimer), whereas institutional feeds reflect consolidated continuous ticks.
- Consolidated SIP vs. Single-Exchange Feeds: The Securities Information Processor (SIP) aggregates all 16 US exchanges. Certain free retail sites pull quotes exclusively from one venue (like BATS or IEX), which can show bid-ask variances of several cents compared to the national consolidated tape.
How Evergreen Hydra Standardizes Portfolio Accounting
For complete clarity and seamless synchronization with our investors' brokerage accounts, the Evergreen Hydra terminal tracks and reports:
- Official Net Asset Value (NAV): Always computed using consolidated official regular-market closing prices.
- Historical Ledgers: Formatted to match institutional broker statements, ensuring complete tax, dividend, and performance auditability.
- Intraday Telemetry: Refreshed continuously so that stop-loss triggers and runner-up replacement queues are always evaluated with verified, live market data.