Sign in

Blog · Forecast and pipeline · Commercial banking

Deposit flight on five relationships: the whole arithmetic on one page

The complete deposit flight calculation on five commercial banking relationships, small enough to check by hand: the trailing twelve month-end balances and the median as baseline, the last three months against the baseline and against the same months last year, the decline rule, the transaction split that says whether the money moved to another bank, the business shrank or the season turned, the balances gone, and the assertion that balances reconcile to receipts and payments, so a reader can reproduce every figure and then run it on their own balance file.

The short answerFive relationships with month-end operating balances. The baseline is the median of the trailing twelve; a decline is three consecutive months below 60 percent of it that the same months last year do not explain. Two relationships decline: one whose outbound transfers to other institutions quadrupled, money moving to another bank, and one whose receipts halved, a business shrinking. One dips in the same months every year and is seasonal. The balances gone are the baseline less the current balance for the decliners. Closing balances equal opening plus receipts less payments each month, or the split is unavailable. Every number can be reproduced by hand.

Deposit flight is a balance against its own history and a transaction split, and on five relationships it can be checked by hand. This page works the baseline, the decline rule, the prior-year test, the split, the balances gone, and the assertion. The last three months are July, August and September.

The balances, in thousands

Relationship Median of trailing 12 (baseline) Jul Aug Sep Same months last year: Jul, Aug, Sep
A $2,100 $1,100 $900 $700 $2,000, $2,050, $2,150
B $800 $400 $400 $300 $780, $820, $790
C $1,400 $700 $600 $800 $720, $650, $760
D $500 $520 $480 $510 $490, $500, $520
E $3,000 $2,900 $1,600 $2,950 $2,950, $3,100, $2,900

The decline rule

Decline if balance < 60% of baseline for three consecutive months, and balance < 60% of the same month last year

Relationship Sep ÷ baseline Three months under 60%? Sep ÷ same month last year Decline?
A 33% Yes: 52, 43, 33 33% Yes
B 38% Yes: 50, 50, 38 38% Yes
C 57% Yes: 50, 43, 57 105% No: seasonal; same every year
D 102% No 98% No
E 98% No: August alone 102% No: one month; a large payment

The transaction split, A and B

Relationship Receipts, 3 months vs prior year Payments to other institutions, vs prior year Reading
A $4.1m vs $4.0m: flat $3.9m vs $0.9m: ×4.3 Moved elsewhere
B $1.1m vs $2.4m: −54% $0.3m vs $0.3m: flat Business shrinking

The balances gone

Gone = baseline − current, for decliners

Relationship Baseline Current Gone Relationship manager Conversation
A $2,100 $700 $1,400 RM-04 Where the money went, and why
B $800 $300 $500 RM-11 The business, and the facility

The assertion

For each relationship and month: closing = opening + receipts − payments. Relationship A, August: opening $1,100, receipts $1,350, payments $1,550: closing $900. Holds. A month that fails by more than the tolerance has a missing transaction file, and that month's split is marked unavailable.

Where it goes wrong, even at five

Baseline as a mean. E's one large receipt month raises the mean; E looks in decline the following month.

No prior-year test. C is on the list every summer.

No transaction split. A and B get the same call; one needs a treasury conversation and one a credit one.

Closures as the measure. A's account is open. It closes next year.

From five to five thousand

The same baseline, rule, prior-year test and split per relationship. Covirage runs it on the balance file and the transaction summary every month. The deposit flight guide covers the measure, and the baseline and norm guide covers why the reference is the relationship's own history.

Questions people ask

Why the median as baseline?

Because one month with a large receipt in it, a customer's sale proceeds, would set a mean baseline the customer never normally holds. The median is the balance the relationship typically carries.

How is seasonal separated?

By the prior-year ratio: this month's balance over the same month last year. A relationship at 40 percent of baseline and 95 percent of last year's same month is doing what it does every year. Both tests must indicate decline.

What is on the transaction side?

Receipts, and payments split by counterparty type: to the customer's own accounts at other institutions, to suppliers, to payroll. No counterparty names. Transfers to other institutions rising while receipts hold is the moved-elsewhere signature.