Understand stop-loss placement methods — Stock-Market notes

WHY do we need a stop-loss at all?

WHY it matters (the math of survival): losses compound against you asymmetrically. To recover from a loss of fraction $L$ , you need a gain of:

$g = \frac{L}{1-L}$

Derivation from scratch: If you lose fraction $L$ , your capital becomes $C(1-L)$ . To get back to $C$ you need a gain $g$ such that $C(1-L)(1+g) = C$ . Cancel $C$ :

$(1-L)(1+g)=1 \implies 1+g = \frac{1}{1-L} \implies g = \frac{1}{1-L}-1 = \frac{L}{1-L}$

The master framework: three questions

Every stop method answers these in a different order:

Where is the setup invalidated? (structure)
How much noise must I tolerate? (volatility)
How much money can I risk? (position sizing)

The golden rule: choose the stop by structure/volatility FIRST, then size the position so the money-risk fits your rules — never the other way round.

Figure — Understand stop-loss placement methods

Method 1 — Structural (Support/Resistance) Stop

HOW: For a long entry, find the most recent meaningful swing low $S$ . Place stop at:

$\text{Stop} = S - b$

where $b$ is a small buffer (e.g. a few ticks or a fraction of ATR) to avoid being wicked out by noise right at the level.

Method 2 — Volatility (ATR) Stop

WHY the three terms? $H-L$ is the intraday range; the other two capture gaps — if the market jumped overnight, the true movement includes the gap from yesterday's close $C_{\text{prev}}$ . Taking the max ensures no real movement is undercounted.

HOW to place it: For a long,

$\text{Stop} = \text{Entry} - k\cdot \text{ATR}, \qquad k \in [1.5,\,3]$

Method 3 — Percentage / Fixed Stop

$\text{Stop} = \text{Entry}\times(1 - p), \quad p = \text{chosen \%}$

Simple, but structure-blind. Best as a cap ("never risk more than 8% per position") layered on top of a structural stop, not as the primary method.

Tying it together: Position Sizing (the 80/20 core)

Common mistake Steel-manning the classic errors

(1) "I'll put a tight stop to lose less money." Why it feels right: smaller ₹ distance = smaller loss per share, feels safer. Why it's wrong: a stop inside the noise band gets hit by random wiggles; you die by a thousand small cuts even when your direction is right. Fix: set stop by structure/ATR, then reduce share count to control money.

(2) "Round the stop to a nice number like ₹200." Why it feels right: round numbers feel clean. Why it's wrong: everyone's stops cluster at round numbers, so price hunts them. Fix: place stops beyond obvious levels, not on them.

(3) "Move the stop further away because I'm sure it'll come back." Why it feels right: protects your ego and the position. Why it's wrong: it breaks the fixed-risk math — your loss is now unbounded. Fix: a stop only ever moves in the direction of reducing risk (trailing), never widening.

Trailing stops (managing the winner)

Once in profit, ratchet the stop up (for longs) to lock gains: e.g. Chandelier Exit:

$\text{Stop}_t = \big(\text{Highest High since entry}\big) - k\cdot \text{ATR}$

The stop only rises, never falls — protecting profit while giving the trend room.

Recall Feynman: explain to a 12-year-old

Imagine you're flying a kite. The stop-loss is the length of string you're willing to let out before you decide "this wind is too crazy, I'm reeling it in." You don't pick the string length by how tired your arm is (your money) — you pick it by how gusty the wind is (the stock's wiggle) and where the trees are (support/resistance). If the wind is wild, give more string but hold fewer kites. If it's calm, short string is fine. And once the kite flies high and safe, you slowly reel the slack in so a sudden gust can't drag it into the trees — but you never let more string out just because you're hoping the wind fixes itself.

Active-Recall Flashcards

What single question decides stop-loss placement?

"At what price is my trade idea invalidated?" — structure decides the stop, not the money you can afford to lose.

Recovery gain needed after a loss fraction L?

g = L/(1-L)

; a 50% loss needs a 100% gain to recover.

Formula for position size from rupee-risk R and stop distance d?

= R/d

where

R=f\cdot C

and

d=|\text{Entry}-\text{Stop}|

Why take max of three terms in True Range?

To capture overnight gaps — real movement can exceed today's high–low range.

ATR stop formula for a long?

Stop

=

Entry

- k\cdot

ATR, with

k

typically 1.5–3.

Why is a fixed tight stop dangerous?

It sits inside normal noise, so random wiggles eject you even when direction is correct.

How may a stop be moved after entry?

Only to reduce risk (trailing in profit direction), never widened.

Reward-to-risk ratio formula?

|\text{Target}-\text{Entry}| / |\text{Entry}-\text{Stop}|

Chandelier trailing stop for a long?

Highest-High-since-entry

- k\cdot

ATR; it only ratchets up.

Wide stop vs tight stop — what changes to keep risk constant?

The number of shares: wider stop → fewer shares, tighter stop → more shares.

Connections

Position Sizing & Risk Management
Support and Resistance Levels
Average True Range (ATR)
Reward-to-Risk Ratio & Expectancy
Trailing Stops & Exit Strategies
Trade Journaling & Reviewing Mistakes

Concept Map

Hinglish (regional understanding)

Intuition Hinglish mein samjho

Dekho, stop-loss ka matlab "haar maan lena" nahi hai — iska matlab hai woh price jahan tumhara trade idea galat saabit ho jaata hai. Agar tumne support se bounce dekh ke buy kiya, toh stop support ke thoda neeche rakho: agar price wahan tak gir gaya, matlab bounce ka reason hi khatam ho gaya, toh nikal jao. Yeh structural stop hai. Doosra tareeka ATR stop hai — har stock apni ek "breathing" karta hai (kitna daily jhoolta hai). ATR usko naapta hai, aur tum Entry minus 2×ATR pe stop lagate ho taaki normal noise se hi tum bahar na phenke jao.

Sabse important baat — stop paise dekh ke mat lagao, chart dekh ke lagao. Paisa control karne ke liye quantity adjust karo. Formula seedha hai: Shares = (Risk in ₹) / (Entry − Stop). Maan lo capital ₹1,00,000 hai, tum 1% yaani ₹1000 risk karna chahte ho, aur stop distance ₹8 hai — toh 125 shares kharido. Agar stop distance zyada ho, toh kam shares; kam ho toh zyada shares. Isse tumhara paisa-risk hamesha ₹1000 hi rehta hai, chahe stop paas ho ya door.

Ek badi galti: log sochte hain "tight stop lagao taaki kam loss ho." Par tight stop noise ke andar hota hai, random wiggle se hi hit ho jaata hai — direction sahi hone ke baad bhi tum bahar. Doosri galti: stop ko peeche khiska dena "abhi wapas aa jayega" ki umeed mein — yeh sabse mehenga blunder hai kyun ki tumhara loss unbounded ho jaata hai. Rule: stop sirf risk kam karne ki direction mein hilta hai (trailing), kabhi widen nahi.

Aur yaad rakho recovery math: 50% loss ke baad 100% gain chahiye wapas aane ke liye — isiliye chhote controlled stops zaroori hain. "SAP the trade": Structure pehle, ATR for noise, Position-size the money.

Test yourself — Entry, Exit & Trade Management

Connections