Divergence between wholesale and retail inflation complicates monetary policy. Discuss with reference to recent trends.

In September 2026, WPI inflation (new 2022-23 base) was 11.39% [1], while CPI inflation was only 5.54% [2]. Wholesale prices are rising about twice as fast as retail prices. The MPC targets CPI at 4% ±2% under the amended RBI Act, 1934, so this gap blurs the signal it uses to set rates.

Recent trends in the divergence

• Fuel-led WPI surge: Fuel & Power inflation was 25.85% in September 2026 [1]. It has stayed above 25% since May, when it was 30.33% [3].
• Base effect plus a real shock: The Fuel & Power index is below its May level, so a low base inflates the YoY figure. Yet the crude index still rose about 18% in a single month [1].
• Muted pass-through: After the West Asia crude spike, excise duty on petrol and diesel was cut by ₹10/litre. Oil companies absorbed under-recoveries instead of raising pump prices [4].
• Food converges: WPI Food inflation was 8.66% [1] and CFPI was 7.74% [2], so food prices are passing through almost fully.

Why the baskets differ

• WPI is heavy on traded goods such as metals and fuel and leaves out services. CPI gives more weight to food and services [5].
• Manufactured products make up about 63% of WPI weight [1].

How it complicates monetary policy

• Conflicting signals: CPI within the band argues for a pause, while WPI points to building cost pressure.
• Lagged pass-through: WPI can feed into CPI with a time lag, and openness carries global prices quickly into WPI [6]. Inflation in manufactured products rose from 8.37% to 9.76% [1].
• Supply-shock dilemma: Rate hikes cannot lower crude prices but do hurt growth. Looking through the shock, however, risks unanchoring inflation expectations.
• Fiscal masking: The excise relief holds down CPI for now [4]. Withdrawing it could make CPI jump suddenly.
• Data uncertainty: The provisional WPI rests on an 83.4% response rate, against 98.97% for final figures [1].
• Measurement flaw: WPI mixes prices from different stages of production. Most countries have moved to SNA-aligned PPIs [7].

Way forward

• The MPC should track core CPI and WPI-manufactured inflation as early warnings, backed by clear forward guidance.
• OEA should scale the trial Input PPI beyond manufacturing and widen the Service PPI [3][7].
• Fuel prices should pass through in phases, in coordination with fiscal policy.

The gap between WPI and CPI comes from different baskets, a global oil shock and fiscal cushioning. With better producer-price data and closer coordination between monetary and fiscal policy, the RBI can protect price stability without hurting growth, in keeping with its flexible inflation-targeting mandate.