Data and Assumptions

Data

All analysis is based on the S&P 500, using SPDR S&P 500 ETF (SPY) as the underlying data source, with all times referenced to US Eastern Time (ET).

The analysis uses SPY ETF price data, scaled to index points. SPY closely tracks the S&P 500 index and provides high-quality intraday price data, making it a reliable proxy for overall index movement.

Analysis updates daily when new market data becomes available (i.e. on trading days).

Note: Brokers and trading platforms often label the same underlying market in different ways (for example “US 500”, “SPX 500”, or “S&P 500”). Twintraday uses SPY data as a liquid, exchange-traded proxy for the S&P 500.

For presentation and strategy modelling, SPY price movements are scaled by a factor of 10 so that values approximate the index level typically quoted for the S&P 500 / US 500. This allows the analysis to be interpreted in index-style points that are comparable with many trading platforms.

Small differences in pricing may still occur due to spreads, broker price feeds, contract specifications, or execution conditions.

• Latest Analysis (Premium): most recent 52 weeks (260 trading days), updated daily
• Example Analysis (Free): the previous 52-week period (the 260 trading days immediately before the Latest Analysis window), updated daily

Assumptions

• Spread: 0.7 points per trade
• Slippage: not included
• PnL (£): assumes a fixed maximum loss amount per day, with position size adjusted accordingly
• Account size / margin: not modelled

Real-world results may differ due to spreads, slippage, execution timing, broker pricing, and market conditions.