What is CPI (Consumer Price Index)?
The Consumer Price Index (CPI) measures the average change in prices paid by urban and rural consumers for a basket of goods and services. In India, CPI is published by the Ministry of Statistics and Programme Implementation (MoSPI) and covers categories like food, housing, transport, and healthcare. Since 2016, the RBI uses CPI as the primary inflation benchmark for monetary policy decisions, making it the most important inflation measure for investors and policymakers.
What is WPI (Wholesale Price Index)?
The Wholesale Price Index (WPI) tracks price changes at the wholesale level before goods reach consumers. Published by the Office of Economic Adviser under DPIIT, WPI covers primary articles, fuel and power, and manufactured products. While no longer the official inflation target, WPI remains crucial as a leading indicator of producer cost pressures. Rising WPI often signals that CPI increases are ahead, as manufacturers pass higher input costs to consumers.
CPI vs WPI: Key Differences
CPI and WPI measure inflation at different stages of the supply chain. CPI reflects what consumers actually pay, including services like housing and healthcare. WPI captures wholesale prices of goods only, excluding services entirely. This is why they can diverge significantly — for example, during 2020-21, WPI was negative while CPI remained elevated, because wholesale commodity prices fell but retail food prices stayed high due to supply disruptions.
For investors: Watch CPI for RBI policy direction and WPI for corporate margin trends. When WPI rises faster than CPI, it may squeeze company margins before firms can raise prices. When WPI falls while CPI holds, margins may expand.
How Inflation Affects Stock Markets
Inflation impacts equity markets through multiple channels. Moderate inflation (2-4%) is generally positive for stocks as it signals healthy demand growth and allows companies to raise prices. However, high inflation (>6%) is typically negative because it triggers RBI rate hikes, increases borrowing costs, compresses PE multiples, and erodes consumer spending power.
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Interest rate impact: High inflation leads to RBI rate hikes, increasing borrowing costs for companies and reducing future earnings in DCF valuations.
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Sector rotation: Commodities and real assets benefit from inflation; high-growth tech stocks and NBFCs suffer. FMCG companies with pricing power tend to outperform during moderate inflation.
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FII flows: Persistent high inflation weakens the rupee, prompting FII outflows as real returns decline for foreign investors.
RBI's Inflation Targeting Framework
Since 2016, India follows a flexible inflation targeting (FIT) framework with a target of 4% CPI inflation and a tolerance band of +/- 2% (i.e., 2% to 6%). The RBI's Monetary Policy Committee (MPC) is mandated to keep CPI inflation within this band. If inflation exceeds 6% or falls below 2% for three consecutive quarters, the RBI must explain the failure to the government and outline corrective steps.
Key takeaway: The 4% midpoint is the RBI's ideal. When CPI is near 4%, expect a neutral monetary policy stance. Above 4%, RBI leans hawkish (rate hikes). Below 4%, RBI leans dovish (rate cuts), which generally supports equity valuations.
What is IIP (Index of Industrial Production)?
The Index of Industrial Production (IIP) measures the short-term changes in the volume of production of a basket of industrial goods. Published monthly by MoSPI with a base year of 2011-12, IIP covers three broad sectors: mining (14.4% weight), manufacturing (77.6%), and electricity (8%). It is one of the earliest indicators of industrial activity and economic momentum in India.
IIP is also broken down by use-based classification: primary goods, capital goods, intermediate goods, infrastructure/construction goods, consumer durables, and consumer non-durables. A rising IIP signals expanding industrial output, which typically supports corporate earnings growth.
For investors: Watch IIP alongside inflation data. Strong industrial production with moderate inflation is the ideal backdrop for equity markets. When IIP contracts while inflation rises (stagflation), it's a warning signal for both growth and value stocks. Capital goods IIP is a particularly useful leading indicator for the capex cycle.
What is PMI (Purchasing Managers' Index)?
The Purchasing Managers' Index (PMI) is a survey-based indicator that captures business conditions in the manufacturing and services sectors. Compiled by S&P Global, India's PMI is based on responses from purchasing managers at around 400 companies. The headline PMI is a composite of five sub-indices: new orders (30%), output (25%), employment (20%), supplier delivery times (15%), and stocks of purchases (10%).
A PMI reading above 50 indicates expansion, while below 50 signals contraction. Unlike IIP (which is a lagging indicator based on actual output data), PMI is a forward-looking indicator released at the start of each month, making it one of the earliest signals of economic momentum. India also has a separate Services PMI and a Composite PMI.
For investors: PMI is released before most other economic data, giving an early read on growth trends. A rising manufacturing PMI with stable input prices (low WPI) is bullish for industrials and capital goods sectors. The prices sub-index within PMI also provides an early read on inflation pressures — a rising prices sub-index often leads WPI increases by 1-2 months.