DSRA sizing illustrator for bank desks

A DSRA sizing illustrator converts scheduled debt service into a target debt service reserve account balance for a stated number of months or payment periods. AFME's project-finance discussion paper places funding of any debt service reserve account in the cash waterfall after debt service and before distributions, and describes the reserve as generally equal to six months of debt service so the project can service debt during periods of tighter liquidity. World Bank guarantee frameworks treat a debt service reserve as a structural credit feature: the Mozambique Sasol appraisal requires a debt service reserve equivalent to at least six months' debt service payments for all senior lenders in that framework.

DSRA sizing illustrator formula

Target DSRA = (periodic debt service) x (number of periods covered)

or, on a months basis:

Target DSRA = (annual scheduled principal + interest [+ included fees]) x (months covered / 12)

Debt service for sizing is the contractual senior schedule used in the facility, not a stressed schedule, unless the term sheet states a stressed sizing rule. Substitutes such as a letter of credit or sponsor guarantee may stand in for cash; the illustrator still states the cash-equivalent target.

Inputs

• Scheduled principal for the sizing window (next six months, next two quarters, or annualised amount)
• Interest on the measured debt for the same window
• Fees included in debt service for reserve purposes, if any
• Cover horizon: months or payment periods (AFME and cited World Bank examples often use six months)
• Funding path: funded at completion, built from early operating cash, LC-backed or guarantee-backed
• Senior scope: which facilities the reserve must cover

The Cote d'Ivoire Azito power appraisal describes a six-month debt service reserve designed to be fully funded at the end of construction, half from debt and equity funds and half from surplus operating cash flow, and notes that the IDA guarantee could be called only after the debt service reserve and escrow account had been accessed and a shortfall remained. That sequencing is institutional context for when a reserve sits inside enforcement waterfalls.

Worked numerical example

Illustrative senior project finance facility after completion:

• Semi-annual principal: 6.0 million
• Semi-annual interest: 4.0 million
• Fees included in debt service: 0.2 million
• Semi-annual debt service = 10.2 million
• Required cover: six months (one semi-annual period in this schedule)

Target DSRA = 10.2 million

If the same facility amortises with uneven sculpting, desks size to the highest upcoming period inside the look-forward window, or to a stated average, according to the term sheet. Example with a look-forward maximum:

• Next three semi-annual debt service amounts: 10.2, 11.0, 10.5 million
• Six-month reserve using the maximum upcoming period: 11.0 million

Funding illustration at completion: 5.5 million from debt and equity at COD, 5.5 million built from surplus operating cash after senior debt service, matching the Azito-style half-and-half pattern without copying that transaction's other terms.

CRE single-asset facilities apply the same liquidity logic to property cash, often with shorter reserve horizons where leases are stable.

Interpretation limits

A DSRA sizing illustrator sets a liquidity buffer. It does not cure weak DSCR or LLCR. Drawing the reserve to pay debt service can keep a period current while depleting the buffer that future periods rely on. Top-ups rank in the cash waterfall ahead of distributions; they are not a cash sweep that prepays principal.

Six months is a common institutional reference in AFME and the cited World Bank appraisals, not a mandatory market constant. Interest-only periods, sculpted amortisation and multi-facility structures change the correct debt-service input. LC or guarantee substitutes change funding cash but not the coverage target unless the facility haircuts the substitute.

Adding DSRA to an LLCR numerator raises reported life cover without raising operating CFADS, a modelling choice that changes the numerator rather than underlying cash generation.