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Kelly Meter

A seatbelt for your account that moves you to cash when markets crash: Kelly Meter

Ed Thorp's Kelly formula on your chart: how much to keep invested and how much in cash, in five steps from 0% to 100%.

$59.60One-time payment · Perpetual personal use

Add to my chart

US$149 (one-time) includes

Full Pine Script v6 source code
8-language panel and install guide
Personal use and editing rights (no redistribution or resale)
30 days of bug-fix support after purchase
Copy button and TXT right after payment

Delivery and refund policy ↗

KELLY METER / REAL PAST PERIOD

Bitcoin's 2017–2018 crash: losing less left more

BTC-USD · 1D · 2017.01.01 → 2018.12.31+769.7%

Over the same two years, holding returned +274.9% and Kelly Meter +769.7% (0.1% cost included).

Hold: +274.9%
Average invested share: 55%

Holding fell as far as −83.4%. Kelly Meter moved to cash on the decline and kept the worst drop to −54.2%.

01 / Period2017.01.012018.12.31730 D
02 / Hold+274.9%-83.4%MAX DRAWDOWN
03 / Kelly Meter+769.7%-54.2%MAX DRAWDOWN · ½ KELLY

Product of (1 + position × daily return) × (1 − position change × 0.1%) − 1 (no dividends or taxes)

Download the period data

PROBLEM → FIX

Harder than buying or selling: how much to put in. Settled.

Watched my account melt in a crash, not knowing when to get out

When the worse of the 1-year and 6-month averages turns negative, it moves to 0% (all cash) and sits the crash out

Lost sleep holding on by gut feel in wild markets

When the last 3 months get shaky it cuts the share and only invests half the Kelly value

Got fooled by indicators that quietly repaint

Daily closes only, never repainted, with 0.1% cost included

No time to work out position sizes every day

An alert fires when the share changes, and the top-right card shows invested and cash at once

01 / WHAT IT DOES

Kelly's three rules protect your account in a crash

No edge, no bet

If the worse of the 1-year and 6-month average return turns negative, it goes to 0% (all cash).

Shaky market, smaller bet

The bigger the last 3 months' swings, the lower the invested share, and it only ever takes half of the Kelly value.

Five steps that rarely flip

Calculated daily, but it changes at most weekly and only by 50+ points. No shorts, no leverage, no repaint.

02 / ON YOUR CHART

Your account's shield, readable at a glance like a traffic light

Instead of tangled lines, a background colour and one big number card show today's invested and cash share.

Your account's shield, readable at a glance like a traffic light · Crash defense card on the chart (S&P 500 2008) — Crash defense card on the chart (S&P 500 2008)
Top-right card: invested 100% · cash 0%, and the 2007.10–2009.3 crash: hold −56.5% · Kelly −6.8%.

03 / EVIDENCE

Worst drops since 2001, in numbers

Stocks, an index, crypto and gold: the worst drop when simply holding versus with Kelly Meter.

Show the full table

All figures are past records with 0.1% cost on every position change, no shorting and no leverage.
Market	From	Hold: worst drop	Kelly Meter: worst drop
S&P 500 (SPY)	2001	−56.5%	−26.9%
Nasdaq 100 (QQQ)	2001	−70.4%	−21.1%
Nvidia	2001	−89.7%	−69.3%
Tesla	2011	−73.6%	−54.5%
Apple	2001	−60.9%	−32.0%
Meta	2013	−76.7%	−31.9%
Bitcoin	2015	−83.4%	−59.9%
Gold	2001	−44.4%	−27.5%

Calculated from Yahoo Finance daily closes (dividends excluded). Figures can differ slightly between data sources.
The TradingView SPY daily card shows the same biggest-crash loss (2007.10–2009.3: hold −56.5% · Kelly −6.8%) as our own Python calculation.

WITHOUT THE INDICATOR

Historic crashes: holding on vs Kelly Meter

How Kelly Meter protected the account in the worst crash periods, from real past records (0.1% cost included).

0.0%

2022 Bitcoin — holding lost −65.3%. Kelly Meter stayed in cash all year.

−5.5%

2008 crisis S&P 500 — holding lost −48.5%. Following the indicator, the loss stopped here.

+3.6%

Dot-com crash 2000.3–2002.10 Intel — holding lost −70.1%. Following the indicator, this much.

04 / INSTALL

Three steps to your chart, right after payment

You get the full Pine Script v6 source and the 8-language install guide right after payment.

01Copy the code or download the TXT after payment
02Paste into TradingView's Pine Editor and save
03Add to the chart; set the panel language and alerts

Past performance does not guarantee future results.

ChartArmory built this from Ed Thorp's formula; it is not affiliated with or endorsed by Thorp.

KELLY METER / FAQ

FAQ

What does a 75% position mean?

75% of the money goes into that market and the other 25% stays in cash.

Did Ed Thorp make this indicator?

No. ChartArmory built it from Thorp's Kelly formula. It is not affiliated with or endorsed by Thorp.

Do past signals change later?

No. It only uses daily closes, so past signals are never repainted, and every position change includes 0.1% cost.

How often does the share change?

At most weekly and only by 50+ points: about 4 times a year across 65 past markets. No edge: cash the same day.

Can I keep using it and edit the code?

One payment: full Pine Script v6 source and 30 days of bug support. Personal use and edits are free; resale is not.

Can I edit or share the code?

You can edit it for personal use. Sharing, redistribution and resale rights are not included.

KELLY METER · V3

Surviving the crash matters more than earning the most

Put a solid crash shield on your chart with Kelly Meter.