What Is Relative Strength in Stocks? A Simple 2026 Guide

Relative strength is just a fancy way of asking a simple question: **is this stock beating the market, or not?** Instead of looking at a stock’s price in isolation, you compare its performance to a benchmark, usually the **S&P 500**, which many traders track with the ETF **SPY**. Here’s the basic idea: - Pick a time window, often **90 days** (about 3 months). - Calculate the stock’s total return over that period (including dividends if you want to be precise). - Calculate SPY’s total return over the same 90 days. - Subtract SPY’s return from the stock’s return. If Apple (**AAPL**) is up **25%** in the last 90 days, and SPY is up **5%**, Apple’s relative strength vs SPY over that period is **+20 percentage points**. If another stock is only up 3% over the same period, its relative strength is **-2 points** (it lagged the market). You’ll see this expressed a few different ways on sites and tools: - As a **simple spread**: “Stock +18% vs SPY +4%” → +14 percentage points. - As a **ratio or line** on a chart: stock price divided by SPY price, plotted over time. - As a **percentile score**: some platforms rank a stock’s performance vs all other stocks. The key takeaway: relative strength is not about whether a stock is “high” or “low.” It’s about whether it’s **stronger or weaker than the crowd** over a specific period. That one idea makes it an incredibly powerful filter when you’re hunting for potential leaders.

You can measure relative strength over any timeframe, but **90 days** hits a sweet spot for many investors: - It’s long enough to matter (a real trend, not just a one‑day pop) - It’s short enough to still catch **new moves** early Imagine two stocks in early 2026: - **NVIDIA (NVDA)**: over the last 90 days, it’s up **30%**. - **SPY**: over the same period, it’s up **5%**. NVDA’s **90‑day relative strength vs SPY is +25 percentage points**. That tells you money has been flowing hard into this name compared with the broad market. Why do many growth‑oriented investors get excited when a stock is **+30 percentage points or more** ahead of SPY over 90 days? 1. **It often marks leadership** A big gap like +30 points usually means institutions (mutual funds, hedge funds, pension funds) are buying aggressively. They move markets over weeks and months. 2. **Leaders tend to keep leading… until they don’t** There’s no guarantee, but in many strong bull phases, the stocks that are far ahead of the index often stay leaders for a while, especially if earnings and revenue are backing up the move. 3. **It filters out “meh” stocks** If SPY is up 8% and a stock is up 6%, that stock might look fine on its own – but it’s actually **underperforming** the market. Relative strength forces you to compare everything to the same yardstick. For a research process, you might say: - Only keep stocks on your “A” watchlist if their **90‑day relative strength vs SPY is +20 to +30 points or more**. - Move stocks that fall behind SPY off the leadership list, even if they’re still up in absolute terms. You’re not predicting the future. You’re simply **following the money** and focusing attention where the strength already is.

This trips up a lot of people: **relative strength** and **RSI (Relative Strength Index)** are not the same thing. - **Relative strength (our topic here)** compares a stock **to something else**, usually an index like SPY, over a period such as 90 days. - **RSI** is a **technical oscillator** that compares a stock’s **recent up days vs down days** to guess whether it’s overbought or oversold. Think of it this way: - Relative strength asks: *“Is this stock beating the market?”* - RSI asks: *“Has this stock gone up too far, too fast in the short term?”* You might see a stock like **Advanced Micro Devices (AMD)** with: - A **strong 90‑day relative strength vs SPY** (say +35 percentage points) - An **RSI above 70**, which many chart tools label as “overbought” Those two things are not contradictory. A strong leader often looks “overbought” on RSI for long stretches while big money keeps piling in. How to use this as a retail investor: - Let **relative strength vs SPY** do the **first filter**: only spend serious time on names that are clearly beating the index. - Use **RSI** (if you like technical tools) to fine‑tune **entry and exit timing**, not to decide which stocks are leaders. If your brokerage or charting app lets you add indicators, you’ll usually find **RSI** under “oscillators,” and a **“relative strength vs index”** or “ratio vs SPY” option under comparison tools. If you’re ever unsure which is which, remember: **RSI is a squiggly line between 0 and 100; relative strength is about performance vs a benchmark.**

You don’t need a Bloomberg terminal to use relative strength. Most basic brokerage and charting platforms give you enough tools. Here’s a simple way to do it with any stock – let’s use **Tesla (TSLA)** as an example. 1. **Pull up a 3‑month (90‑day) chart for TSLA** On your broker’s site or app, set the time frame to around 3 months. 2. **Add SPY on the same chart** Look for a button like “Compare,” “Add symbol,” or “Overlay,” and type in **SPY**. 3. **Switch to percentage view if possible** Many tools let you toggle to “% change” instead of dollar price. This shows how much TSLA and SPY have moved in percentage terms from the start of the period. 4. **Read the numbers** Suppose over the last 90 days: - TSLA is **up 22%** - SPY is **up 4%** That means TSLA’s **relative strength vs SPY is +18 percentage points**. 5. **Log it in a simple spreadsheet** You can make a very basic table: - Column A: Ticker (TSLA, AAPL, NVDA, etc.) - Column B: 90‑day return - Column C: SPY 90‑day return - Column D: RS (B minus C) Then sort by Column D from highest to lowest. The names at the top are your **current relative strength leaders**. If you use more advanced platforms like TradingView or similar charting tools, you can: - Plot a **TSLA/SPY ratio line** and see if it’s trending up (outperforming) or down (lagging). - Scan the whole market to find stocks that are outperforming SPY by a certain threshold over 3 months. The main point: make relative strength a **repeatable step** in your process, not something you eyeball once in a while.

Let’s put this into a simple weekly routine you could actually stick to, even with a day job. 1. **Build a starter universe** Start with names you understand or hear about often: - Big tech (AAPL, MSFT, NVDA, AMD, META) - Popular consumer names (AMZN, COST, MCD) - Whatever sectors you care about 2. **Once a week, calculate 90‑day relative strength vs SPY** - Check each stock’s **3‑month % change** in your broker or on a free charting site. - Note SPY’s 3‑month % change. - Subtract SPY’s number from each stock’s number. 3. **Create two simple lists** - **Leaders**: stocks with **+20–30 percentage points or more** vs SPY over 90 days. - **Laggards**: stocks that are **flat or behind SPY**. 4. **Focus your research time on the leaders** For stocks in the leaders bucket, dig a little deeper: - Check **recent earnings** (for example, what happened at the latest quarterly report for NVDA or AMZN?). Did revenue and profits jump or just the stock price? - Look at recent news: product launches, AI partnerships, big contract wins, regulatory approvals, etc. 5. **Watch for leadership changing hands** Over time, you’ll notice: - Some names stay near the top of your RS list for months. - Others fade as the story cools off or the company stumbles. By making relative strength your **first filter**, you’re not trying to out‑guess Wall Street. You’re just letting the market **show you where demand already is**, and then deciding which of those strong names are worth a closer, fundamental look. You still control your decisions. Relative strength simply helps you spend your limited time where the odds of finding something interesting are higher.

Relative strength is simple, but there are a few easy traps to avoid. 1. **Treating any gain as “strength”** A stock being up doesn’t mean it’s a leader. If **MSFT** is up 6% in 90 days but SPY is up 8%, MSFT actually has **negative relative strength** over that period. Always compare to SPY (or your chosen benchmark). 2. **Using too short a window** A stock can pop 10% in a day on news and then fade. If you only look at 1‑week performance, you’ll constantly chase noise. A **90‑day window** smooths out a lot of that randomness. 3. **Ignoring fundamentals completely** Relative strength can flag leaders like **AMZN** or **COST**, but it doesn’t tell you *why* they’re strong. Earnings growth, margins, debt, competition – that still matters. Think of RS as the **metal detector**, and fundamentals as the **digging and inspecting** part. 4. **Confusing RS with RSI** Remember: **RS = performance vs SPY**; **RSI = overbought/oversold oscillator**. You can absolutely have a high‑RS stock with an overbought RSI and vice versa. 5. **Forcing predictions** Relative strength is descriptive, not prophetic. It tells you what **has** been strong, not what **must** happen next. A stock like NVDA can have incredible relative strength and still stumble if a future earnings report disappoints. If you stay aware of these pitfalls, relative strength turns into a calm, repeatable habit: each week, you check which stocks are beating the market by a meaningful margin and then decide which of those deserve your attention.