How to Analyze Banking Stocks — NPA, CASA, NIM, and Other Key Metrics Explained

Understanding the banking business model is essential before diving into the numbers. Banks are financial intermediaries that accept deposits from savers and lend money to borrowers. They make money primarily through the spread between the interest they earn on loans and the interest they pay on deposits. This is fundamentally different from manufacturing or service companies, which is why banks require a completely different set of analytical tools.

Banks face three unique risks: credit risk (borrowers defaulting), interest rate risk (changes in interest rates affecting margins), and liquidity risk (depositors withdrawing funds). Analyzing banking stocks requires assessing how well management manages these risks while growing the loan book profitably. The quality of a bank's loan book, its deposit franchise, and its capital position are the three pillars of banking analysis.

In India, the banking sector is divided into public sector banks (like SBI, PNB, Bank of Baroda), private sector banks (like HDFC Bank, ICICI Bank, Kotak Mahindra, Axis Bank), and foreign banks. Private sector banks have generally delivered higher returns due to better operational efficiency and lower NPAs. For a broader view of sector analysis, refer to our guide on industry analysis.

Net Interest Income (NII) is the difference between the interest income a bank earns from its lending activities and the interest it pays to depositors. It is the primary source of revenue for most banks. Net Interest Margin (NIM) is NII expressed as a percentage of average earning assets. NIM is the single most important measure of a bank's core profitability, similar to gross margin for a manufacturing company.

For example, if HDFC Bank earns ’1,00,000 crore in interest income, pays ’50,000 crore in interest expenses, and has average earning assets of ’20,00,000 crore, its NIM would be (’1,00,000 - ’50,000) / ’20,00,000 = 2.5%. A bank with a consistently high and stable NIM indicates strong pricing power and efficient operations. HDFC Bank has historically maintained NIM of 4-4.5% on its domestic book, among the best in India.

NIM is influenced by the bank's loan mix (retail loans earn higher interest than corporate loans), its deposit mix (more CASA deposits lower funding costs), and the interest rate cycle. A rising interest rate environment typically benefits banks that have more floating-rate loans than fixed-rate deposits. Comparing NIM trends across banks and over time reveals which banks have sustainable competitive advantages. See our guide on interest rate impact on sectors.

CASA stands for Current Account and Savings Account. These are low-cost deposits that banks use to fund their lending. Current accounts typically pay zero or very low interest, while savings accounts pay around 3-4% in India. Term deposits (fixed deposits) pay higher rates, typically 6-8%. The CASA ratio is the percentage of total deposits that come from current and savings accounts. A higher CASA ratio means cheaper funding for the bank.

For example, a bank with a CASA ratio of 45% might have an average cost of deposits of around 3.5%, while a bank with a CASA ratio of 30% might have a cost of deposits of 5%. This 1.5% difference in funding cost directly impacts NIM and profitability. HDFC Bank has one of the highest CASA ratios in the Indian banking sector at approximately 40-45%, giving it a significant competitive advantage over peers with lower ratios.

CASA ratio also reflects the strength of a bank's franchise. A high CASA ratio indicates deep customer relationships, strong branch network, and trust in the brand. Building a high CASA franchise takes years of consistent service and investment in branches and technology. This is why well-established private banks trade at premium valuations — their deposit franchises are difficult to replicate. For more on competitive advantages, see our guide on economic moat.

Asset quality is arguably the most important factor in banking analysis. A bank can have great NIM and CASA, but if its loans are not repaid, profitability will collapse. The key metrics are Gross NPA ratio (total bad loans as a percentage of total loans), Net NPA ratio (bad loans minus provisions as a percentage of total loans), Provision Coverage Ratio (PCR, provisions as a percentage of gross NPAs), and the slippage ratio (fresh additions to NPAs during a period).

For example, if a bank has ’10,00,000 crore in loans, ’50,000 crore in gross NPAs, and ’35,000 crore in provisions, the Gross NPA ratio is 5%, Net NPA ratio is 1.5% ((50,000 - 35,000) / 10,00,000), and PCR is 70% (35,000 / 50,000). A high PCR means the bank has set aside enough money to cover potential losses from bad loans. The best Indian private banks (HDFC Bank, Kotak) typically have Gross NPAs below 2%, while weaker public sector banks have historically seen Gross NPAs above 10%.

Slippages are loans that have newly become NPAs during the quarter. A rising slippage ratio is a warning sign. Watch for trends: are NPAs rising or falling? Is the bank increasing provisions adequately? Also look at restructuring, which are loans whose terms have been modified to prevent them from becoming NPAs. A high level of restructured loans can be a ticking time bomb. For understanding how these risks affect valuation, read our guide on credit ratings.

Capital Adequacy Ratio (CAR) measures a bank's capital relative to its risk-weighted assets. It is the buffer that protects depositors and creditors from bank losses. Regulators mandate minimum CAR levels — in India, the Reserve Bank of India requires banks to maintain a minimum CAR of 11.5% (including the Capital Conservation Buffer of 2.5%). Banks with CAR significantly above the minimum are better positioned to absorb unexpected losses and grow their loan books.

Within CAR, Common Equity Tier 1 (CET1) is the highest quality capital, consisting primarily of equity shares and retained earnings. A strong CET1 ratio (typically above 12-13%) indicates a bank has ample high-quality capital. The leverage ratio (Tier 1 capital divided by total assets, not risk-weighted) is another measure gaining importance — it prevents banks from taking on excessive leverage even on low-risk assets.

The Liquidity Coverage Ratio (LCR) measures a bank's ability to survive a 30-day liquidity stress scenario. High-quality liquid assets (government bonds) as a percentage of expected net cash outflows should be above 100%. These ratios may seem technical, but they directly impact a bank's ability to pay dividends, grow, and weather economic downturns. Banks with strong ratios are safer investments. For a broader understanding of financial safety, review our guide on debt service coverage ratio.

Banking stocks are typically valued using the Price to Adjusted Book Value (P/ABV) ratio rather than the P/E ratio used for most other companies. The reason is that a bank's book value (equity capital) is more stable than its earnings, which can be volatile due to provisions. P/ABV tells you how much the market is willing to pay for each rupee of the bank's net worth. A P/ABV above 1 means the bank is valued at a premium to its book value.

The P/ABV a bank commands depends on its return on equity (ROE), growth rate, asset quality, and franchise strength. High-quality private banks like HDFC Bank have historically traded at P/ABV of 4-5x when their ROE was 18-20%. Weaker public sector banks with low ROE and high NPAs often trade at P/ABV below 1x (i.e., at a discount to book value). The Price to Earnings (P/E) ratio is used as a secondary metric but is less reliable for banks.

When valuing banks, compare P/ABV and ROE across peers. A bank with higher ROE should command a higher P/ABV. Also consider the dividend yield, as well-capitalized banks with strong earnings often pay attractive dividends. Track the bank's book value growth over time — consistent growth in book value per share is a sign of sustainable value creation. For a deeper understanding of how ROE drives valuation, see our guide on ROE.

Ready to analyze banking stocks? Use our stock market data to research banking sector stocks, or explore our stock screeners to find investment opportunities. This content is educational and does not constitute financial advice.