Interest Income: The Core Revenue Line of a Lender

Interest income is what a lender earned in a stated period on the money it has lent and on the securities it holds, counted before a single rupee of it is paid away to anybody. Suvarna Commercial Bank Limited earned Rs 18,600 crore of it in one stated year. Interest income arrives as an amount rather than a rate, and turning it into a rate means choosing an asset base to divide it by.

Here is the shape underneath that answer, and it is worth getting straight before any arithmetic. A lender puts money into things that pay it interest, and it takes money in from people it pays interest to. Interest income is the whole of the first flow with none of the second one removed. Every other measure of a lender is built either by subtracting something from this line or by dividing this line by something. That is why quoting it as though it were a result is the commonest mistake made about lenders.

What is interest income, and what is it not?

Interest income is the total interest a lender earned in a stated period on what it has lent and on what it holds. Two exclusions do most of the damage when they are forgotten, and both of them are exclusions of things people expect to find inside the number. The first is that interest income is counted before anything at all is paid to the people who funded the lender. The second is that it excludes fees, commissions, and every other rupee the lender earned that is not interest.

The everyday version is a stall on a street outside an office building. At the end of the day the cash box holds four thousand rupees. Four thousand rupees is the takings, and the takings are not the earnings. The vegetables were bought that morning on credit from a wholesaler who has to be paid. Nobody who has run a stall for a week confuses the two. Interest income is the cash box at the end of the day, and the wholesaler has not been paid yet. The whole of what follows is the paying.

One more thing sits inside the definition and it is easy to walk past. Interest income for Suvarna Commercial Bank Limited is Rs 18,600 crore for the year, and every one of those rupees left somebody else's hands. Borrowers paid the part that came off advances and the issuers of the securities paid the part that came off investments. Interest income is one side of a claim and it always has a matching side: what the lender counted as income, somebody else counted as cost, and the two net to zero across the pair of them. That is not a technicality. The matching side is the reason a lender's revenue behaves differently from a factory's, and the failure set out below is built on it.

Which lines on a lender's asset side actually produce it?

Two lines, and no others. Advances produce interest income because a borrower pays for the use of the money. Investments produce interest income because the security pays a coupon to whoever holds it. Everything else Suvarna Commercial Bank Limited holds produces none of it: the cash in its vaults, the balance it keeps at the central bank, and the buildings it operates from are all real assets and none of them pays interest to the bank.

The split for the year runs as follows. Advances of Rs 1,44,000 crore and investments of Rs 60,000 crore add to Rs 2,04,000 crore of assets that earn. Total assets are Rs 2,40,000 crore. The difference, Rs 36,000 crore, is the slice that earns nothing. The non-earning slice is 15.0 per cent of the balance sheet. The underlying record does not divide it any further, so how much of it is the balance at the central bank and how much is a branch in a town somewhere cannot be said.

Is interest income a rate or an amount?

An amount. Rs 18,600 crore, in rupees, for one stated year. No rate is there until somebody divides that amount by an asset base, and the moment they do, they have made a choice that the reader can neither see nor check unless it is written down. The single most useful habit to build about lenders costs nothing: whenever a per cent appears, the question is what sat underneath it.

Do the division twice on the same numerator and watch what happens. Rs 18,600 crore over earning assets of Rs 2,04,000 crore is 9.12 per cent for the year. The same Rs 18,600 crore over total assets of Rs 2,40,000 crore is 7.75 per cent for the year, and that second one is exact rather than rounded. Both are correct arithmetic. Both are yields. The two yields are 1.37 percentage points apart, and the whole of that distance is the Rs 36,000 crore of assets that earn nothing.

A shortcut runs between the two readings, exact in one direction and only nearly exact in the other. The difference is worth seeing properly. Earning assets are 85.0 per cent of the balance sheet, so the second yield is 0.85 times the first. The unrounded yield, 9.1176470588 per cent, multiplied by 0.85, lands on 7.75 per cent exactly. The printed 9.12 per cent, multiplied by 0.85, gives 7.752. The figure 7.752 prints as 7.75 at two decimals and is not the same number. The shortcut looks exact because the rounding hides the difference. Rounding after the multiplication and rounding before it are two different operations, and an account that writes the second one as an equality has quietly taught the reader something false.

How much of what a lender earns in interest actually stays with it?

The answer is the single most useful thing to carry away about the shape of a lender, so the subtraction is worth taking slowly. Interest income for the year is Rs 18,600 crore. Interest expended for the same year is Rs 11,160 crore. Net interest income is Rs 7,440 crore. Put that in rupees per hundred and it sticks: of every Rs 100/- of interest Suvarna Commercial Bank Limited earned in the year, Rs 60.00 went straight back out to the people who funded it and Rs 40.00 stayed.

People who arrive from any other kind of business find this the surprising part. Sit with it for a moment. A manufacturer that gave away sixty rupees in every hundred of sales before touching wages, rent or electricity would be in a bad way. The sixty rupees is not a cost of production at all, so a bank doing exactly that is doing the ordinary thing. The sixty rupees is the price of the raw material, and the raw material of a lender is other people's money. The money a lender lends was borrowed first, and interest expended is what it costs to have borrowed it.

How Banks Make Money: what happens to the first line before it becomes the last?

The count is the point, so walk it from the top and count the steps. Interest income of Rs 18,600 crore, less interest expended of Rs 11,160 crore, gives net interest income of Rs 7,440 crore. Add other incomeEverything a lender earned in the period that is not interest: fees, commissions, charges and the like. The contents of other income are covered separately. of Rs 2,400 crore and total income is Rs 9,840 crore. Take off operating expensesThe cost of running the lender itself, being staff, premises, technology and the rest. Operating expenses exclude interest and they exclude provisions. of Rs 5,040 crore and operating profit is Rs 4,800 crore. Take off provisionsThe charge a lender takes in the period against advances it expects will go bad. A provision is a cost booked now for a loss expected later. of Rs 1,800 crore and profit before tax is Rs 3,000 crore. Take off tax at 25.0 per cent, being Rs 750 crore, and profit after tax is Rs 2,250 crore.

Five steps stand between the first line and the last, four of them subtractions and one of them the addition of other income, so a reader who quotes any single line as the bank's performance has quoted one step out of five. Count them once and the habit sets: less interest expended, plus other income, less operating expenses, less provisions, less tax. Each of the four subtractions is a completely different kind of item. Interest expended is the price of the raw material. Operating expenses are the cost of running the place. Provisions are a charge taken now for a loss expected later. Tax is what the state takes at the end.

One more reading comes free from the walk and it says a great deal about what kind of lender this is. Net interest income of Rs 7,440 crore is 75.61 per cent of total income of Rs 9,840 crore, and other income of Rs 2,400 crore is the remaining 24.39 per cent. Roughly three rupees in every four of what Suvarna Commercial Bank Limited counts as total income came from lending money rather than from doing anything else, and that balance is what makes a lender a lender rather than a business that happens to have a banking licence.

Which of a bank's two revenue figures is its revenue?

Here is the honest version of a problem most explanations skip. A bank has two figures that both behave like revenue, both are defensible, and they differ by more than a factor of two. The first is everything it earned: interest income of Rs 18,600 crore plus other income of Rs 2,400 crore, which is Rs 21,000 crore. The second is total income of Rs 9,840 crore. Total income takes interest expended off before adding other income, and a bank's own reporting leads with it. Neither is wrong. Neither is labelled revenue.

Now put one profit over both of them and watch the answer move. Profit after tax is Rs 2,250 crore. Against everything earned, Rs 21,000 crore, that is 10.71 per cent. Against total income, Rs 9,840 crore, the same Rs 2,250 crore is 22.87 per cent. One profit, one year, one bank, two defensible bases, and the second reading is more than double the first. The gap between the two bases is exactly the Rs 11,160 crore of interest expended, and whether that Rs 11,160 crore sits above the line or below it is the whole of the difference.

Both bases answer a real question. Everything earned answers what the whole operation brought in. Total income answers what was left to run the bank with once the money had been paid for. The fault is never choosing one; the fault is quoting a margin without saying which one was chosen. That is the habit worth carrying away.

When does interest on an advance stop being income at all?

There is a point past which a lender may no longer count interest on an advance as income, even though the borrower still owes every rupee of it. Before that point, contractual interest and reported interest income move together. After it, they part company: the contract still says the interest is due, and the lender's income statement stops carrying it. Recognition and entitlement are two different questions, and mixing them up is how a reader concludes that a bank has forgiven a debt when it has done nothing of the kind.

Where that point sits, how an advance gets classified as a non-performing advanceAn advance that has stopped being treated as performing, so it is reported separately and carries its own charge. The treatment of such an advance afterwards is covered separately., and what happens to interest a lender has already taken into income sit with the Reserve Bank of India, and every one of the three moves. Each appears below as a named row with the address printed inside it. A row filled in from recollection goes wrong the morning the requirement changes, with nothing to warn the reader that it has. A row like that is a liability rather than a service.

Does a lender that takes no deposits earn interest income the same way?

A lender without deposits earns the same line and pays for its money somewhere else, and putting the two side by side is the fastest way to see what interest income is actually made of. Rukmini Finance Limited lends, takes no deposits at all and funds itself in the market. In the same kind of stated year it earned interest income of Rs 2,610 crore on a book of Rs 18,000 crore, a yield of 14.50 per cent on that book for the year, and it paid interest expended of Rs 1,224 crore. Net interest income is Rs 1,386 crore.

Now do the rupees per hundred for the second lender. Rs 1,224 crore over Rs 2,610 crore means Rs 46.90 of every Rs 100/- of interest earned went out again, so Rs 53.10 stayed. More of every hundred stays at Rukmini Finance Limited than at Suvarna Commercial Bank Limited, where Rs 40.00 stayed, and that difference is about where each lender buys its money rather than about which one is run better. One takes deposits and pays for them at one price; the other borrows in the market and pays for that at another. The underlying record holds one year and no cycle for either of them, so neither figure is evidence about what either way of funding a lender achieves.

One thing about the second lender is worth naming precisely because it is missing. The record splits Suvarna Commercial Bank Limited's assets into an earning part and a non-earning part. The split into earning and non-earning is what allowed two different yields to be struck on one interest income figure. The record carries no such split for Rukmini Finance Limited: it holds one book of Rs 18,000 crore and nothing that divides it, so the denominator problem cannot even be posed on the second lender from what exists here. Naming that gap is the honest move. Inventing a split to make the comparison symmetrical would produce a line that reads exactly like a reported one and is not.

What does interest income on its own refuse to tell?

Three silences, and each one has cost somebody a wrong conclusion. Interest income says nothing about what the money cost, nothing about whether the borrowers will actually pay, and nothing about the size of the book that produced it. The three fail in different directions, so take them one at a time.

On cost: a lender whose interest income rose because rates rose, while its own funding cost rose further, reports a bigger first line and a smaller net interest income in the same year on the same book. The headline improved and the thing worth reading got worse. On collection: interest income is what was earned under the contracts, and whether the borrowers pay is a separate question answered by a different set of figures entirely. On size: Rs 18,600 crore is a large number and it means nothing on its own. Set against Rs 2,04,000 crore of earning assets, the figure becomes 9.12 per cent for the year.

The record behind these figures carries less than a reader might assume, and the temptation to fill a gap is strongest exactly where the gap matters. There is one year and there are two lenders. There is no quarterly series, no split of the advance book by segment or by sector, no maturity buckets, no restructured book, no written-off book, no borrower detail, no branch or employee count, no division of the Rs 36,000 crore of assets that are neither advances nor investments, and no split of interest expended between deposits and the other Rs 24,000 crore of liabilities the bank carries. An invented line would read exactly like a reported one, and that is the precise failure worth preventing.

Who actually reads this line, and what do they do with it?