Liquidity Planning and Liquidity Simulation: Methods and Practice (2026)
Liquidity planning is the forward view on cash in and cash out, and therefore on the bank balance. In the short term it is planned directly, from concrete payment flows such as open invoices, payroll and tax dates, typically weekly across 13 weeks. In the medium term it is derived indirectly from the earnings plan, adjusted for the change in working capital, capital expenditure and financing. A liquidity simulation goes one step further: it encodes the drivers behind those flows, so a changed assumption recalculates the entire liquidity path instead of shifting a row in a table.
The distinction matters in practice, because the questions that concern liquidity are almost always variants. What if the major customer pays 30 days later? What if the bank does not renew the facility? A single liquidity plan answers none of these; it merely describes one path.
The two methods and when each fits
| Direct method | Indirect method | |
|---|---|---|
| Starting point | Concrete cash receipts and payments | Earnings plan (planned P&L) |
| Typical horizon | 4 to 13 weeks | 12 to 24 months |
| Granularity | Daily or weekly | Monthly |
| Data source | Open items, bank statements, payment dates | Plan plus balance sheet linkages |
| Strength | Precision in the near term | Connection to corporate planning |
| Weakness | No link to the earnings plan | Too coarse for the coming weeks |
Both are necessary, and conflating them is the most common error. Maintain only the 13-week view and you will not see the growth trap, because it lands the quarter after. Plan only indirectly and monthly and you will not see the squeeze in week three, because monthly figures average it away.
Why the earnings plan is not enough
Three quantities sit between profit and bank balance that either do not appear in the P&L or behave differently there:
- Working capital. Revenue growth ties up cash in receivables and inventory. A company can lose liquidity while profit rises.
- Capital expenditure. It hits liquidity immediately, the P&L only spread across the useful life.
- Financing. Principal repayments are not an expense and therefore never appear in the P&L, but they consume cash. Only the interest portion is an expense.
Liquidity planning is therefore not a separate document but the third layer of integrated financial planning. Without the balance sheet layer in between, the working capital effect cannot be calculated, which makes balance sheet planning the precondition rather than the optional extra.
Where the legal thresholds sit
Tolerance on liquidity is low, and in Germany the thresholds are explicit. Under § 17 InsO a company is illiquid when it cannot meet its due payment obligations. Federal Court of Justice case law treats this as indicated where the liquidity gap amounts to at least 10 percent of due liabilities and cannot be closed within three weeks. Only funds actually available, or realisable with high probability within that period, count towards closing it, such as confirmed and drawable credit lines.
Once illiquidity occurs, § 15a (1) InsO applies: “Der Antrag ist spätestens drei Wochen nach Eintritt der Zahlungsunfähigkeit und sechs Wochen nach Eintritt der Überschuldung zu stellen” (the petition must be filed within three weeks of illiquidity and six weeks of over-indebtedness). Three weeks is not enough time to build a liquidity plan from scratch. For managing directors of limited-liability entities, the upstream duty under § 1 StaRUG applies as well, to monitor developments that could threaten the survival of the company on an ongoing basis; advisory practice recommends an integrated plan updated during the year with an 18 to 24 month liquidity horizon.
The context remains tight: between January and April 2026, German courts registered 8,551 filed business insolvencies according to the Federal Statistical Office, 6.7 percent more than in the same period the previous year, with expected creditor claims of around 13.9 billion euros.
From plan to liquidity simulation
A simulation differs from a plan in the questions it can answer. Four elements make the difference:
- Drivers instead of rows. Cash receipts follow from revenue and days sales outstanding, not from a typed-in total. Change the collection period from 40 to 55 days and the model recalculates the whole path. The method is that of driver-based planning.
- Variants instead of a version. Two or three scenarios with named triggers, not one plan with a safety margin. A safety margin conceals which risk is actually meant.
- A live link to actuals. Every forward view starts from the last closed month. If that arrives as an export, updating is an operation rather than a project, see simulation on DATEV data.
- Visibility of the cause. Not just when the balance turns negative, but what drives it: collections, a tax payment, debt repayment or capex? Only the cause can be addressed.
The typical simulation questions
| Question | Driver changed | Where it shows up |
|---|---|---|
| What if the major customer pays 30 days later? | Days sales outstanding in that segment | Cash receipts, overdraft utilisation |
| What if we grow revenue 20 percent? | Volume, working capital ratio unchanged | Receivables, inventory, funding requirement |
| What does the investment really cost? | Timing and payment schedule of capex | The liquidity trough between payment and effect |
| Do we stay within the facility at the seasonal low? | Monthly distribution of revenue | Lowest bank balance in the year |
The second row is the one most often overlooked. Growth is a liquidity risk, and it is the only one that presents itself as success in a purely earnings-based view.
Outlook
The tooling for short-term liquidity is well served: bank connectivity, categorisation and a 13-week view are largely standard today. The gap is the connection forward, between that payment view and the corporate plan it should follow from. That is where the difference lies between a liquidity overview and a statement about which business decision produces which liquidity path. For companies without a controlling function, this step is becoming accessible, because the data foundation arrives structured every month and the linkage logic is not company-specific.
Frequently asked questions
How far should a liquidity plan reach?
On two tracks: a rolling 13 weeks at weekly resolution for operational steering, plus 12 to 24 months monthly for financing and early warning. IDW S 11 requires at least twelve months for a going-concern assessment, with liquidity examined on a weekly or monthly basis.
What is the difference between liquidity planning and cash flow planning?
In practice the terms are used almost interchangeably. Where a distinction is drawn, cash flow planning means the statement derived indirectly from the earnings and balance sheet plan, while liquidity planning means the direct near-term payment view. A complete model contains both.
How often does a liquidity plan need updating?
The short-term view weekly, the medium-term view monthly as the books close, and additionally whenever a material assumption changes. The third condition matters most and is overlooked most often.
When does a liquidity gap become critical?
Legally the guidance is clear: under Federal Court of Justice case law, a liquidity gap of at least 10 percent of due liabilities that cannot be closed within three weeks indicates illiquidity. Commercially, the attention threshold should sit considerably earlier, because countermeasures need lead time.
Is an overdraft facility a substitute for liquidity planning?
No. A credit line is a buffer, not a forecast, and it is only as reliable as its availability. In the insolvency law assessment, only genuinely drawable lines count in any case. Without projecting utilisation of the facility, you learn about the squeeze when it arrives.