Hey trader,
It took roughly 50 years for the S&P 500 to climb from 500 to 1,500 (late 90’s).
It ran from 1,400 to 7,500 in under 20 years (past two decades)
Nothing changed in finance. Energy and staples didn’t change either.
Everybody hands you earnings and AI as the answer. That explanation doesn’t cover the angle of this chart.
One structural change explains it. That shift happened in 2001.
Almost nobody talks about it.
I’ll show you what it was, why it turned this market into a one-way escalator, and the exact tell that fires before the escalator reverses.
Here’s how it works.
The Rule Change Nobody Talks About
Before 2001, US stocks traded in fractions. That was a leftover from an 18th-century Spanish dollar convention.
IBM and Microsoft were quoted in eighths (1/8)and sixteenths (1/16). An eighth is 12.5 cents.
The smallest increment allowed was a sixteenth, which came out to 6.25 cents. The tightest spread you’d ever see was about six and a quarter cents.
Most names traded 25 cents wide. Plenty of them sat 50 cents wide.
In 1999, a bill went into Congress for SEC-mandated decimalization. Chairman Arthur Levitt pushed it to bring US markets in line with global decimal standards.
The phase-in started in September 2000. The full launch hit on April 9, 2001.
Every stock went from a 25-cent or 50-cent spread down to a single penny.
How A Penny Killed Volatility
That penny did something few traders ever connect to their own account.
Market makers used to scalp 25-cent spreads. Now they scalp what’s called teenies, a tenth of a tenth of a cent, done millions of times a day on server farms.
Pull up time and sales on any liquid name. You’ll see fills like 58.139 and 58.1314.
Tightening every spread from 25 cents to a penny compresses volatility by default. The math does that on its own.
That compression is the real reason the tape grinds higher and the VIX sits pinned near the floor. A penny-wide market keeps stocks levitated for years.
This is volatility compression. It’s been running since 2001.
The Tell That Widens Before The Drop
Compression doesn’t last forever. The same mechanism that levitates the tape works in reverse the moment liquidity dries up.
When a pricing engine can’t find enough buyers and sellers, it stops quoting tight. The spread widens out.
That widening is your warning.
Here’s the homework I’d hand you if you worked for me. Learn the normal bid-offer spread on the names you actually follow:
- Apple runs about four cents wide on a calm day.
- Bank of America, a $58 stock, sits a penny wide.
- Morgan Stanley trades around 12 cents.
Watch those numbers every morning. When Morgan Stanley drifts from 12 cents to 16, then 18, then 25, you’re in what Brandon Chapman calls a volatility regime change.
Picture Morgan Stanley down $19 with a dollar-wide spread. The liquidity has vanished.
At that point they can gap the whole tape lower before you ever get out.
Stocks rally when spreads tighten. They drop when that chasm opens up.
You can track this across hundreds of names from a single screen.
A shift in rates, the dollar, or a COVID-style shock is all it takes to flip compression into expansion. That’s the road to the 35% to 40% correction I keep warning you about.
The widening shows up before the headlines do. Build the habit of watching it now.
Professor Jeffrey Bierman
Creator of the Genesis COG System
