July 30, 2026
What is Cost of Funds (CoF)? How Borrowing Costs Impact Lenders
The Answer
Cost of Funds (CoF) measures the interest rate a bank or NBFC pays on deposits and wholesale borrowings. A Cost of Funds Spike is a sudden increase in this blended borrowing rate, which squeezes Net Interest Margins (NIM) unless lending yields can be raised at the same speed.
Why it Matters
CoF is the bank's raw material cost. Spikes occur during tight system liquidity or credit rating downgrades, forcing the lender to offer higher deposit rates to retain retail cash. High CoF destroys banking profitability.
Sentinel Insight
āDuring deposit wars, mid-tier banks spike their CoF to gather funds. Monitor deposit franchise density to spot interest rate exposure.ā
š How to Interpret
In Risk Context
Flagium tracks Cost of Funds Spike under flag F9 (Weight: 10) in the Efficiency and Earnings domain. It triggers when borrowing rates jump by >30 bps QoQ.
Deep Dive
Cost of Funds Spike: Funding Cost Pressures
For a bank or NBFC, profitability is governed by the spread between what it charges on loans (Yield on Advances) and what it pays to depositors and bondholders (Cost of Funds).
The Blended Cost of Funds Equation
Where interest-bearing liabilities include:
- Retail Deposits (Savings accounts, fixed deposits).
- Wholesale Funding (Certificates of Deposit, interbank borrowings).
- Long-term Debt (Bonds, debentures).
How Flagium Detects Cost of Funds Spikes
Flagium monitors interest expenses relative to blended liabilities. If the Cost of Funds spikes by QoQ, the engine triggers the F9 efficiency flag.
The Cost of Funds Spike Cascade
When the central bank hikes repo rates or system liquidity tightens, a spike in CoF happens:
- Wholesale Reliance: Lenders that depend on short-term wholesale market borrowings (e.g. NBFCs and mid-sized private banks) feel the pinch first. The cost of issuing Certificates of Deposit (CDs) spikes instantly.
- Retail Deposit Wars: Banks must raise Fixed Deposit rates to compete for depositor funds, which increases the average cost of savings accounts.
- CASA Compression: As FD rates hit 7.5%+, depositors move funds out of 3.5% savings accounts, causing the CASA Ratio to deteriorate, pushing up the blended CoF.
- Margin Compressions: Unless the bank's loan book is fully tied to floating benchmarks (like EBLR or MCLR) and can reset rates immediately, its Net Interest Margin compresses.
Forensic warning signs
Watch out for:
- Cost of deposits rising faster than yield on assets: Compressing the bank's net interest spread.
- High CD issuance: Sudden rise in Certificate of Deposit (CD) issuance relative to core deposit growth.
- Credit rating downgrades: A rating downgrade (e.g., from AAA to AA+) immediately spikes wholesale borrowing yields.
Detect risk early
Flagium tracks these signals across multiple quarters to help you avoid structurally weak companies before it reflects in price.
View blended cost of funds trends āš