What Is the 3-5-7 Rule in Trading? (And Buffett's 90/10 Rule Explained for Indian Traders)

"The secret to great trading isn't finding great trades. It's having rules - and actually following them every single time."

Understanding 3-5-7 Rule Trading and Buffett 90/10 Rule is essential for modern market participants. Throughout this guide, we dive deep into 3-5-7 Rule Trading, Buffett 90/10 Rule, Trading Psychology, Risk Management, Algo Trading Edge, highlighting how core concepts like Trading Psychology and Risk Management shape consistent performance.

Here's a truth most trading courses won't say out loud: the reason most retail traders lose money isn't a lack of strategy. It's a lack of discipline. They know what to do. They just don't do it consistently.

They risk 15% on one trade because it "felt like a sure thing." They let a losing position run because they didn't want to book the loss. They chase a breakout at 2:45pm even though their system only takes morning setups.

Sound familiar?

The smartest traders - from Buffett to the most successful systematic traders in India - have cracked the same insight: you don't win by being clever. You win by having clear rules and following them without exception.

This post breaks down the two most talked-about trading rules on the internet right now - the 3-5-7 Rule and Buffett's 90/10 Rule - and ends with the one thing both of them quietly point toward.

The 3-5-7 Rule in Trading, Explained Without the Jargon

If you've been searching for this, you've probably seen a lot of complicated explanations. Here's the simple version: it's a risk management framework built on three numbers that protect your capital, prevent overexposure, and ensure your wins outweigh your losses.

Nothing more complicated than that. Here's what each number actually means:

The math behind why this works is elegant. Even if you only win 4 out of 10 trades, as long as your winners are at least 2x your losers, you come out ahead. The 3-5-7 rule structurally makes this happen - it forces you to size down losses and size up targets.

"⚠ The Uncomfortable Truth: Most traders know this rule. Or something like it. They've read about it, they agree it makes sense, and then they break it the moment a "really good setup" appears. Because when you're staring at a live chart at 10:30am and Nifty is moving hard, discipline is a feeling - not a system. And feelings lie."

Warren Buffett's 90/10 Rule - And What It's Really About

In his 2013 letter to Berkshire Hathaway shareholders, Warren Buffett revealed the instructions he left in his will for how his wife's inheritance should be managed after he's gone. The strategy was strikingly simple:

This rule caused a storm when it was revealed - because here was the greatest stock-picker of all time telling his own family: don't try to pick stocks. Don't try to time the market. Just follow a simple, systematic rule and be patient.

The 90/10 rule is based on one core insight: the S&P 500 has returned roughly 10% annually before inflation over nearly a century. Most active fund managers - people paid millions to beat that - fail to do so consistently. So Buffett's argument is this: systematic, passive exposure to the market beats the average "smart" investor. Every time. Over the long run.

For Indian retail traders, the equivalent would be systematic, rules-based exposure to Nifty or Sensex - through ETFs, index funds, or a well-defined systematic strategy - rather than trying to out-predict the market on every trade.

"💡 Buffett's 70/30 Rule: People also search for Buffett's "70/30 rule" - which is actually associated with his mentor Benjamin Graham rather than Buffett directly. Graham recommended a flexible 25%-75% range between equities and bonds, adjusting based on market conditions. The 70/30 interpretation means 70% equities, 30% bonds - more conservative than Buffett's 90/10, better suited for investors closer to retirement or with lower risk tolerance."

What Both Rules Are Actually Saying (This Is the Part Nobody Talks About)

Here's the thing that jumped out at us when looking at both the 3-5-7 rule and Buffett's 90/10 rule side by side:

Both of them are fundamentally about removing human discretion from execution.

Buffett's 90/10 rule says: stop trying to be clever. Follow the system. Don't deviate based on how you feel about the market today.

The 3-5-7 rule says: follow the percentages. Every trade. No exceptions. Don't let excitement or fear change your position sizing.

Both rules exist precisely because traders - even brilliant ones - make terrible decisions when they improvise. The rules are the guardrails. The rules are the product.

And here's where it gets interesting for systematic traders in India.

If you have a rule-based strategy - meaning your entry, exit, and position sizing are defined by specific conditions - then every time you deviate from your rules, you are making your system worse, not better. You're adding noise where there should only be signal.

The Human Problem: Knowing the Rule Isn't the Same as Following It

Let's be real. You've probably experienced this exact sequence:

You have a trading rule: "Only take trades when RSI is below 35 on the 15-minute chart." Clear. Simple. Works on paper.

It's 11:45am. The market is running hard. RSI is at 48. Your gut says this is about to break out. You take the trade anyway. It goes against you. You hold hoping it recovers. It doesn't. You exit at a 2x loss of what your stop should have been.

You didn't break the rule because you're a bad trader. You broke it because you're human. That's what humans do under pressure.

This is the gap between rule-based trading in theory and rule-based trading in practice. And this gap is exactly why serious traders eventually move toward automation.

When Rules Become a System - The Case for Automation

Here's what algo trading actually is, stripped of all the jargon: it's your trading rules, converted into a program that executes them without emotion, without distraction, and without exception.

The 3-5-7 rule? An algorithm enforces it on every single trade. The 3% limit, the 5% exposure cap, the 7% target - baked in, non-negotiable, executed correctly whether you're watching or not.

Buffett's 90/10 principle? It's literally the systematic, rules-based philosophy applied to market participation. Don't try to beat it. Follow the system. Be consistent.

Manual Execution of Rules

Automated Execution of Rules

This is not a pitch for algo trading as some magical money-printing machine. The rules still need to be good. The edge still needs to exist. But if you have a working, rule-based strategy - one that has generated consistent returns when you've managed to follow it - automation removes the one variable that's been sabotaging your results: yourself.

"✓ The Honest Summary: Rules are only as good as the consistency with which they're followed. Buffett's 90/10 rule works because his trustee will follow it without deviation for decades. The 3-5-7 rule works when it's applied on every single trade without exception. The traders who realise this - and automate their execution - stop fighting their own psychology and start letting their edge compound."

Already Have a Strategy? Let's Automate It.

Frequently Asked Questions

What is the 3-5-7 rule in trading?

The 3-5-7 rule is a risk management framework: never risk more than 3% of your capital on a single trade, keep total exposure across all open trades under 5%, and aim for at least 7% profit (or a 2:1 reward-to-risk ratio) on winning trades. It protects capital, prevents overexposure, and ensures your winners outweigh your losers over time.

What is Warren Buffett's 90/10 rule?

Buffett's 90/10 rule, outlined in his 2013 letter to Berkshire Hathaway shareholders, recommends investing 90% of capital in a low-cost S&P 500 index fund and 10% in short-term government bonds. The core principle is systematic, rules-based investing - not trying to outsmart the market through active management or emotional decision-making.

What is Warren Buffett's 70/30 rule?

The 70/30 rule is more closely associated with Buffett's mentor Benjamin Graham than with Buffett himself. Graham recommended a flexible 25%-75% range between equities and bonds, and the 70/30 interpretation means 70% equities and 30% bonds. It's more conservative than the 90/10 rule and better suited for investors with lower risk tolerance or shorter time horizons.

Why do traders break their own rules even when they know better?

Because trading decisions happen in real time under financial pressure, and human psychology is not wired for consistent, emotion-free execution. Fear causes early exits, greed causes traders to hold losses, and excitement breaks position sizing rules. Knowing a rule and consistently following it are two completely different skills - which is why serious traders eventually automate their execution.

How do I automate my rule-based trading strategy in India?

If your strategy has clear entry conditions, exit conditions, and position sizing logic, it can be automated. A custom development firm converts your strategy into code, integrates it with your broker API (Zerodha, Fyers, Angel One, Upstox), and deploys it on a cloud server that executes trades automatically - whether you're watching or not. Most simple strategies take 4-8 weeks to automate from scratch.

Already Have a Strategy? Let's Automate It.

At Arkalogi, we convert your trading logic into fully automated systems - integrated with your broker, backtested on real market data, and deployed on a live server. You describe your strategy in plain English. We handle everything else. Book a free honest assessment on WhatsApp to chat with us. No sales pitch. Just clarity on what's possible and what infrastructure you need to avoid common failure modes.