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ISM PMI explained: why 50 is the number to know

One number, one line at 50. Above it, business is growing. Below it, it's shrinking. The ISM PMI is one of the easiest reports to read, once you know that one rule.

Beginner guide · 5-minute read · Updated 2026-10-21

What the ISM PMI is

PMI stands for Purchasing Managers' Index. Purchasing managers are the people at companies who buy supplies. They see early whether orders are rising or falling.

Every month, a group called the Institute for Supply Management (ISM) asks hundreds of these managers simple questions: Are new orders higher, lower or the same as last month? Is production? Hiring? Prices?

The answers become one number, the PMI.

• Who publishes it: the Institute for Supply Management (ISM), a private group, not a government agency
• Manufacturing PMI: the first business day of the month at 10:00 am ET
• Services PMI: the third business day of the month at 10:00 am ET
• Schedule: on the ISM release calendar (dates can move for holidays)

The 50 line

This is the one rule to remember.

• Above 50: more managers said "higher" than "lower". The sector is growing.
• Below 50: more said "lower". The sector is shrinking.
• Exactly 50: no change.

Here's the thing. The PMI shows how many companies saw growth, not how much they grew. A reading of 55 doesn't mean output rose 5%. It means more companies said "up" than "down".

Manufacturing vs services

Manufacturing gets a lot of attention because it comes out first and reacts early to changes in demand. Services covers far more of the economy.

The sub-indexes worth knowing

Each PMI is built from smaller pieces. They use the same 50 rule. A few that traders watch:

• New orders: are customers ordering more? This often turns before the headline does.
• Employment: are companies hiring? It can hint at the monthly jobs report.
• Prices: are companies paying more for supplies? A rising prices index can hint at pressure in the CPI report later.

The prices index is often the one that moves markets when inflation is the big worry.

Why 10:00 am matters

Most big US reports come out at 8:30 am ET, before the stock market opens. The ISM PMI comes out at 10:00 am ET, half an hour after stocks open at 9:30 am.

That means stocks are already trading when the number lands. A surprise can cause a fast move in the middle of the morning session, not just a Gap at the open. If you trade the open, the 10:00 am candle is worth planning for.

Why markets react

The PMI is one of the first readings each month on how business is doing. It comes out before GDP and before most other monthly data.

• Strong PMI: can mean a stronger economy, and maybe higher rates for longer.
• Weak PMI: can mean a slowing economy, and maybe lower rates ahead.
• High prices index: can mean inflation pressure, whatever the headline says.

The dollar, index futures, stocks and bonds can all react. See how interest rates affect stocks for the chain.

What a beginner can do on PMI days

1. Mark 2 days a month. The first business day (manufacturing) and the third (services), both at 10:00 am ET.
2. Check the calendar for a busy morning. On the first Friday of some months, the jobs report at 8:30 am and the PMI at 10:00 am can land close together.
3. No new trades 15 minutes before 10:00 am. If you're in a trade, decide in advance. Spreads can widen and stops can slip (Slippage).
4. Wait 15–30 minutes after. Then follow your normal plan: bigger chart first, a candle body closing past the last turning point, size from your stop with the position size calculator.

Common mistakes

• Reading 55 as "5% growth". It's a count of up vs down answers, not a size.
• Forgetting the 10:00 am time. It hits during the stock session, not before it.
• Watching only the headline. New orders and prices often tell the real story.
• Mixing up ISM and S&P Global. Two different reports, two different times.

Questions