Cash flow
How to build a business cash reserve for economic uncertainty
A cash reserve gives a business time to respond when income arrives late or essential costs rise. The useful target is based on its commitments and risks, not a universal number of months.
Quick answer
Identify essential monthly outgoings, model plausible disruptions and set a reserve target the business can build without missing current obligations. Keep tax provisions separate and make sure the money is accessible when the plan requires it. An unused credit limit is not the same as cash.
Key points
- Base the target on a stress scenario and recovery time.
- Exclude money already needed for tax or committed purchases.
- Rebuild the reserve after using it and review the target as the business changes.
Calculate the cash needed to keep operating
List essential payroll, premises, utilities, minimum supplier commitments and finance payments. Distinguish genuinely discretionary spending from costs that cannot be stopped immediately. Include notice periods and unavoidable contractual payments.
If essential outgoings are £15,000 each month and a plausible disruption could remove receipts for two months, £30,000 is a starting scenario before existing receipts, mitigation and exceptional costs. It is not a recommended target for every firm. A diversified consultancy and a seasonal retailer can need very different buffers.
Build the reserve through a sustainable rule
Set an affordable transfer based on actual surplus cash after current obligations, rather than a percentage of sales that ignores margin. Use stronger trading periods and review discretionary distributions where appropriate. Agree ownership and approval rules for accessing the reserve.
For example, a business that can genuinely set aside £1,000 a month will need 18 months to reach £18,000 before interest or withdrawals. If that is too slow for the risk, consider improving collections, reducing fixed commitments or changing the target—not pretending the existing gap is already covered.
Match the savings account to the emergency
Compare access restrictions, notice periods, withdrawal limits, fees and provider eligibility. A higher advertised return can be unsuitable if wages become due before the money can be withdrawn. Keep an immediately accessible portion where the stress plan requires it.
Check deposit protection for the specific business and authorised banking group, particularly when balances are spread across brands. Do not assume every account or institution qualifies. Business reserve money needed soon is not normally money to expose to volatile investments.
Define when to use and replenish the reserve
Record approved purposes, decision-makers and a replenishment plan. A reserve can address a temporary shock; using it repeatedly for ordinary losses is a warning that prices, costs or the operating model need attention.
Business loans can provide investment capital or bridge an affordable timing gap, but borrowing simply to display a larger bank balance creates repayment and interest commitments. Show reserve cash, tax provisions and borrowing availability separately in your forecast so the same protection is not counted twice.
Include customer and supplier concentration
A business with a few large customers can experience a bigger shock from one late payment than a business with many smaller receipts. Model the largest plausible interruption rather than relying only on average monthly sales. Consider how long replacing that customer or supplier would take.
For example, if a single customer provides £20,000 of monthly receipts, losing one payment can overwhelm a reserve based on a much smaller average variation. Include the essential payments still due while the issue is resolved. Do not assume every cost falls proportionately with revenue. The target should reflect the exposure and recovery options, while recognising that no practical reserve can insure against every possible event.
Keep business and personal reserves clearly separated
A director’s savings are not automatically company cash, and company money is not automatically available for personal emergencies. Keep the ownership, authority and accounting treatment of any transfer clear. If an owner plans to support the business, record the conditions and obtain advice on the structure.
The same principle applies when a business operates through several entities. A healthy bank balance in one company does not establish that another can use it freely. Map the obligations of the actual borrower before assessing business-loan affordability. Separation makes the reserve easier to monitor and prevents an apparent buffer being counted simultaneously against company bills, household spending and another business’s commitments.
Compare reserves with insurance and credit realistically
Insurance, reserve cash and committed finance can each help manage risk, but they differ in eligibility, timing and certainty. Review policy wording and claims conditions rather than assuming a disruption generates an immediate payment. Retain funds for the initial response where the plan requires them.
Likewise, an undrawn facility may carry conditions or be unavailable for the intended purpose. Show it separately and understand fees and repayment obligations. A reserve consists of money already available to the business; credit creates an additional liability when drawn. Combining tools can be sensible, but avoid counting several protections that all depend on the same uncertain assumption, such as a claim being accepted before payroll is due.
Use a trigger for rebuilding and reviewing the target
Agree what happens after an authorised withdrawal. A plan might pause discretionary distributions and resume affordable transfers until the reserve reaches its agreed level. The exact rule should fit the business and any legal obligations rather than being copied from another firm.
Review the target when fixed costs, customer concentration or financing commitments change. A reserve that covered several months before a new lease or hire may cover much less afterwards. Record the date and assumptions behind the target so management can explain why it remains appropriate. If the business cannot rebuild the reserve because ordinary trading consumes it repeatedly, investigate the underlying margin and cash cycle rather than treating the depleted balance as normal.
Common questions
- Should VAT money count as my reserve?
- Money needed for an expected tax liability is already committed. Treat it separately when assessing genuinely available emergency cash.
- Is an overdraft enough instead?
- An overdraft may be useful but access can be conditional and interest applies when used. Assess the facility alongside cash rather than treating the two as identical.
Sources
Sources were checked on 16 October 2026. A source check confirms what these publications said on that date; it is not a financial review of any product.
- How to create a cash flow forecast — British Business Bank
- Getting your business ready for finance — British Business Bank