RelativeStrength

Relative Strength (RS) measures how a stock’s price performance compares to a benchmark — almost always the S&P 500 — over a defined lookback period, typically 12 months. Unlike RSI, which is an internal momentum oscillator derived from a stock’s own price history, RS is an external comparison: it answers the question “is this stock beating the market?” Momentum traders use RS to filter thousands of stocks down to the handful of genuine leaders worth trading.

Key Takeaways

• RS is not RSI — RS compares a stock to the S&P 500 benchmark; RSI measures internal price momentum on a 0–100 scale.
• Stocks with an IBD RS Rating of 80 or above are in the top 20% of all performers; O’Neil’s research found major winners averaged an RS Rating of 87 before their big advances.
• The RS Line making a new 52-week high before the stock price does is a leading indicator of institutional accumulation, often signaling a breakout weeks in advance.

How Relative Strength Works

The RS Line is the core practitioner’s tool. It is calculated by dividing the stock’s closing price by SPY’s closing price at each point in time:

RS Line = Stock Price / SPY Price

Plotting this ratio over time reveals whether the stock is outpacing or lagging the market. A rising RS Line during a broad market decline is the clearest signal of genuine leadership — it means institutional buyers are accumulating the stock even as others sell the index.

IBD’s RS Rating condenses this into a 1–99 percentile score, where 99 means the stock outperformed 99% of all listed stocks over the past 12 months. IBD weights the most recent 3 months more heavily than the prior 9 months to capture emerging momentum. Some quant systems use shorter windows — 6-month or 3-month momentum factors (as in the Fama-French momentum factor) — but IBD’s 12-month weighted rating is the most widely used in active trading.

The screening workflow most momentum traders use:

1. Filter for RS Rating of 85 or above (eliminates 80–90% of the universe)
2. Confirm the RS Line is at or near a 52-week high
3. Require a constructive base pattern (flat base, cup-and-handle, tight consolidation)
4. Enter only on a breakout with volume at least 40% above average

Practical Example

It is early November 2023. SPY is up 12% year-to-date. A trader runs a screen for RS Rating of 90 or above and finds META at RS 96 — it has outperformed 96% of all listed stocks over the past 12 months. The RS Line broke to a new 52-week high in October while SPY was still recovering from its summer correction, flagging institutional accumulation weeks before the mainstream narrative caught up.

META forms a 7-week flat base with volume drying up to its lowest weekly levels in months. The trader enters at $320 on a breakout above the base pivot, confirmed by volume running at 2x the 50-day average. Risk is set to the 8-week low at $295 — a $25 risk per share, or 8.4%.

Position sizing: $30,000 account, 1% risk = $300 maximum loss. $300 / $25 risk per share = 12 shares (~$3,840 position). META reached $550 by early 2024, a 72% gain from the entry. The RS screen identified leadership months before price made it obvious.

Relative Strength measures how a stock performs compared to the S&P 500 over the past year. Stocks with high Relative Strength are outpacing the market and are often the first to break out when conditions improve. Traders use it to find leaders before they make their biggest moves.

Common Mistakes

1. Confusing RS with RSI. RSI is a bounded oscillator (0–100) based solely on the stock’s own recent price changes. RS is an unbounded ratio comparing the stock to an external benchmark. Using RSI to assess relative market performance will give you the wrong answer.
2. Buying high RS in a downtrend without confirming price action. A stock can rank RS 90 in a bear market simply by falling 5% while the S&P 500 falls 20%. High RS alone is not bullish — price must be in an uptrend or forming a constructive base, and volume must confirm accumulation.
3. Ignoring the RS Line direction in favor of the rating. A stock with RS 88 and a falling RS Line is losing leadership. A stock with RS 82 and an RS Line just breaking to new highs is gaining it. The trend of the line matters as much as the rating level.
4. Missing sector RS. RS works at the sector level too. During the 2022 bear market, energy sector ETFs like XLE showed rising RS Lines against SPY for months before individual energy stocks like XOM and CVX became widely discussed. Screening for leading sectors first narrows the search for individual leaders.

How JournalPlus Tracks Relative Strength

JournalPlus lets traders tag each trade with a setup type and record the RS rating at entry, making it straightforward to review whether high-RS entries consistently outperform lower-RS ones in your own trading history. The performance analytics break down win rate and average R-multiple by setup tag, so you can quantify exactly how much RS filtering improves your results over time.