GDP, IIP and PMI are three regular health checks on the economy: Gross Domestic Product (GDP) measures everything the country produces, the Index of Industrial Production (IIP) measures factory output, and the Purchasing Managers' Index (PMI) is a monthly survey of businesses. Markets track all three because company profits ultimately grow out of the economy they operate in.
What does each one tell me?
GDP is the broadest check-up. It adds up the value of all goods and services produced in India in a period, farms, factories, software, haircuts, everything. When GDP grows fast, more is being made, sold and earned. It is published quarterly, months after the quarter ends, so it is the most complete but also the slowest of the three.
IIP zooms into industry alone: mining, manufacturing and electricity. It is published monthly and answers a narrower question. Did factories produce more this month than the same month last year? Arjun, who holds shares of a fictional pumps maker, watches IIP because his company lives inside that number.
PMI is the quickest and the least official. Every month, a private data firm asks purchasing managers at hundreds of companies whether orders, output and hiring rose or fell. Answers are crunched into one number where above 50 means expansion and below 50 means contraction. Because it is a survey of what businesses are seeing right now, it lands earlier than IIP or GDP, a rough but fast pulse-check.
| Indicator | Covers | How often | Speed |
|---|---|---|---|
| GDP | Entire economy | Quarterly | Slow, most complete |
| IIP | Mining, manufacturing, electricity | Monthly | Medium |
| PMI | Business survey (manufacturing/services) | Monthly | Fastest, least official |
Why do markets care about these numbers?
Because earnings follow the economy. A growing economy generally means more loans disbursed, more cars sold, more cement poured, the raw material of company profits. Growth data also feeds central-bank thinking: weak numbers can make room for rate cuts, strong numbers can support keeping rates higher, which links these releases to why markets react to RBI policy. Alongside inflation data, they form the calendar of releases that can move markets on days when nothing changed in your portfolio itself.
Why can a "good" number still disappoint the market?
Here is the part that confuses most beginners. Suppose GDP growth comes in strong, and the Nifty 50 slips anyway. The reason is the expectations game: prices adjust to forecasts before the release. If analysts expected even stronger growth, the actual number is a letdown relative to what was already priced in, and markets often react to that gap rather than to the number itself.
The same logic runs in reverse. A weak print can be greeted with a rally if it was less bad than feared, or if it raises hopes of rate cuts. This is a specific case of a general rule worth internalising early: prices move on surprises and changed expectations, not on old news.
Things to keep in mind
- GDP is broad but slow; IIP is narrower but monthly; PMI is fastest but survey-based. Read them together, not in isolation.
- Markets often react to the gap between the released number and expectations. Memorise this, it explains most "why did the market fall on good news?" days.
- Single readings are noisy and get revised; trends over several releases matter far more than any one print.
- None of these numbers predicts where the market goes next. They describe the economy, and the market has usually formed its own view already.
Read next
What is inflation (CPI and WPI), and how does it affect the market? — The number that drives interest rates, and through them nearly everything else.