What it means
A bank funds its lending mostly with other people's money, principally deposits and borrowings, and only a slice of it belongs to shareholders. Core capital is that shareholder slice, restricted to the components that are permanently available and carry no obligation to pay anyone back.
Loss-absorbing capacity is the whole point: capital that has to be repaid on a fixed date cannot absorb a loss when it is needed. The usual build is straightforward.
Start with ordinary share capital and share premium, add retained earnings and certain reserves, add qualifying non-cumulative perpetual preferred shares where the rules allow it, then deduct goodwill, most other intangibles and specified regulatory adjustments. The deductions matter because goodwill has no value in a crisis, and counting it would flatter the buffer exactly when accuracy matters most.
Two ratios do the reporting work. The core capital ratio divides core capital by risk-weighted assets, where each exposure is weighted for how risky it is, so government bonds carry a low weight and unsecured business lending a high one.
The leverage ratio divides core capital by average total assets with no risk weighting at all, acting as a plain check that the risk model has not been gamed. Minimum requirements are set by regulators and layered, with a base requirement plus conservation and countercyclical buffers, and extra amounts for banks judged systemically important.
Falling below the buffer levels does not close a bank down, but it typically restricts dividends, share buybacks and bonuses until the position is rebuilt. That is why bank boards manage to a self-imposed target comfortably above the legal floor.
The concept has spread beyond banking supervision. Analysts use core capital to compare institutions across countries where accounting differs, and it is the anchor for return on equity comparisons and for judging whether a bank can absorb a large credit loss without raising fresh shares.
For a non-bank reader, the plain-English version is the amount of genuinely permanent money standing between depositors and a loss.
In practice
Real-world examples.
Example
A community bank holding a core capital ratio of 12% decides to buy a smaller rival. Because the acquisition creates goodwill that is deducted from core capital, the finance team models the post-deal ratio at 9.4% and reduces the cash portion of the offer to stay above its internal 10% floor.
Example
A bank facing a wave of commercial property write-downs sees retained earnings fall, dragging its core capital ratio from 11.5% to 9.2%. The board cancels the interim dividend and pauses its buyback to rebuild the buffer rather than issue shares at a depressed price.
Example
A supervisor examining a bank with a strong 13% risk-weighted ratio but a 4% leverage ratio concludes that the risk weights are doing too much work. The bank is asked to hold additional capital until the unweighted measure improves.
Formula
Calculation
Core capital = Ordinary share capital + Retained earnings and eligible reserves + Qualifying non-cumulative perpetual preferred shares - Goodwill and other deducted intangibles. Core capital ratio = Core capital / Risk-weighted assets. Leverage ratio = Core capital / Average total assets.
A mid-sized bank reports ordinary share capital and premium of $420,000,000, retained earnings of $260,000,000 and qualifying perpetual preferred shares of $40,000,000, which sum to $720,000,000. It deducts goodwill of $70,000,000 and other intangibles of $30,000,000, a total of $100,000,000, leaving core capital of $720,000,000 - $100,000,000 = $620,000,000. With risk-weighted assets of $6,200,000,000, the core capital ratio is $620,000,000 / $6,200,000,000 = 10.0%. Average total assets are $7,750,000,000, so the leverage ratio is $620,000,000 / $7,750,000,000 = 8.0%.Case study
Seen in the real world.
Kestrel Union Bank is an illustrative, fictional regional lender with core capital of $620,000,000 and risk-weighted assets of $6,200,000,000, giving the 10.0% ratio described above. Its strategy committee wanted to grow unsecured small business lending by $600,000,000, an attractive margin business but one carrying a 100% risk weight.
The modelling was sobering. Adding $600,000,000 of fully weighted exposures would take risk-weighted assets to $6,800,000,000, and with core capital unchanged the ratio would fall to $620,000,000 / $6,800,000,000 = 9.1%, below the 9.5% internal floor the board had set. To hold the ratio at 10.0% the bank would need core capital of 10% x $6,800,000,000 = $680,000,000, meaning $60,000,000 of fresh equity or retained profit.
In this fictional case the board phased the growth over three years so that retained earnings could fund most of the requirement, and raised a smaller amount of equity than the full plan would have needed. The example illustrates the everyday tension in bank strategy: lending growth is limited not by demand but by the capital standing behind it.
Watch out
Common mistakes.
- Reading the core capital ratio as a share of total assets. The denominator is risk-weighted assets, so a 10% ratio does not mean the bank holds 10% of its balance sheet in equity.
- Counting goodwill as part of the buffer. Goodwill is deducted precisely because it cannot absorb losses, and forgetting the deduction badly overstates the bank's strength.
- Treating the regulatory minimum as a target. Operating close to the floor restricts dividends and buybacks and leaves nothing for a bad quarter, so banks manage to a margin above it.
Questions
People also ask.
What is the difference between core capital and Tier 1 capital?
In practice they describe the same thing, with core capital being the older and more descriptive name for the Tier 1 category used in current banking rules.
Why does a leverage ratio exist alongside the risk-weighted one?
It acts as a backstop, because risk weights depend on models and assumptions, while total assets are a simple figure that cannot be optimised away.
Can a bank increase core capital without issuing shares?
Yes, by retaining profits rather than paying them out, by selling non-core businesses, or by reducing risk-weighted assets through lower-risk lending.
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