Working Capital Analysis
DSO, DIO, DPO, and the cash conversion cycle in PE due diligence
~20 min read
Working capital is the lifeblood of any operating business. It represents the cash tied up in day-to-day operations: the gap between when a company pays its suppliers and when it collects from its customers. For PE buyers, working capital analysis goes far beyond the simple 'current assets minus current liabilities' formula taught in introductory accounting. It is a window into the operational efficiency of the business, the quality of its customer relationships, and the sustainability of its cash flow.
In this lesson, we focus on the key efficiency ratios that PE buyers use to diagnose working capital health, the cash conversion cycle that ties them together, and the working capital peg mechanism that protects buyers in purchase agreements.
The Three Efficiency Ratios: DSO, DIO, and DPO
PE buyers break working capital into three component metrics, each measuring how efficiently the company manages a different part of the operating cycle:
Days Sales Outstanding (DSO) measures how quickly the company collects payment from customers. DSO = (Accounts Receivable / Revenue) x 365. A DSO of 45 means the company waits an average of 45 days to collect after making a sale. Rising DSO suggests customers are paying more slowly, the company is extending more generous terms to win business, or there are collection problems.
Days Inventory Outstanding (DIO) measures how long inventory sits before being sold. DIO = (Inventory / COGS) x 365. A DIO of 60 means the company holds an average of 60 days of inventory. Rising DIO may indicate slowing demand, overproduction, or accumulation of obsolete stock. For manufacturers and distributors, DIO is one of the most important operational metrics.
Days Payable Outstanding (DPO) measures how long the company takes to pay its suppliers. DPO = (Accounts Payable / COGS) x 365. A DPO of 35 means the company pays suppliers an average of 35 days after receiving goods or services. Higher DPO means the company is using supplier financing to fund operations, but excessively high DPO can strain supplier relationships or signal financial distress.
Cash Conversion Cycle (CCC)
The cash conversion cycle measures the total number of days between when a company pays for its inputs and when it collects cash from selling the finished product. A CCC of 70 days (e.g., DSO of 45 + DIO of 60 - DPO of 35) means the company must fund 70 days of operations out of its own cash before customers pay. A shorter CCC is better because it means less cash is trapped in operations. Some businesses (like Amazon) achieve a negative CCC, collecting from customers before paying suppliers. In PE, improving the CCC is a common value creation lever: tightening collections, reducing inventory, and negotiating better payment terms with suppliers can free significant cash.
Seasonality and Its Impact on Working Capital
Many businesses experience seasonal swings in revenue and working capital that can distort point-in-time metrics. A retailer with 40% of annual revenue in Q4 will show dramatically different working capital in September (inventory build-up, low receivables) versus January (inventory drawdown, high receivables from holiday sales). A landscaping company may have minimal receivables in January but large receivable balances in August.
For PE buyers, seasonality creates two practical challenges:
- Choosing the right measurement period: A trailing twelve-month average of working capital is more representative than any single month-end snapshot. QoE reports typically analyze monthly working capital over at least 24 months to identify seasonal patterns.
- Timing the close: If a deal closes at a seasonal peak in working capital (e.g., right after a retailer has built inventory for the holiday season), the buyer will deliver a higher working capital at close, potentially triggering a payment to the seller under the working capital peg mechanism. Sophisticated buyers time the close to coincide with a period of 'normal' working capital, or they adjust the peg to reflect seasonal expectations for the specific closing month.
The Working Capital Peg in Purchase Agreements
The working capital peg (also called the target NWC or working capital true-up) is a negotiated dollar amount written into the purchase agreement. It represents the 'normal' level of net working capital the seller agrees to deliver at closing.
The mechanics work as follows:
- During diligence, the buyer and seller agree on a target NWC, typically based on an average of trailing monthly NWC (often 12 or 24 months), potentially adjusted for seasonality or known anomalies.
- At closing, the purchase price is calculated using an estimated NWC, and the deal closes.
- Within 60-90 days after closing, the actual NWC at the closing date is calculated and compared to the peg. If actual NWC exceeds the peg, the buyer pays the seller the difference. If actual NWC falls short, the seller refunds the buyer.
This mechanism is one of the most contentious parts of PE deal negotiations. Disputes commonly arise over which line items are included in NWC versus treated as debt-like items, the appropriate averaging period for setting the peg, and how to handle seasonal businesses. Sellers have an incentive to push for a lower peg (delivering less working capital), while buyers want a higher peg (receiving more working capital with the business).
Reading Working Capital Trends
A PE buyer is evaluating a $60M-revenue industrial parts distributor. The company's working capital metrics over the past three years show concerning trends:
- DSO: 38 days (Year 1), 44 days (Year 2), 53 days (Year 3). Collections are slowing. Management attributes this to two large customers negotiating extended terms, but the buyer notes that these customers represent only 15% of revenue, meaning the slowdown is more widespread.
- DIO: 52 days (Year 1), 58 days (Year 2), 71 days (Year 3). Inventory is building. Management claims it is pre-buying to lock in favorable pricing, but the QoE team identifies $2.1M in slow-moving SKUs (over 180 days old) that may need to be written down.
- DPO: 32 days (Year 1), 30 days (Year 2), 28 days (Year 3). The company is paying suppliers faster, not slower, reducing its use of supplier financing.
- CCC: 58 days (Year 1), 72 days (Year 2), 96 days (Year 3). The cash conversion cycle has expanded by 38 days over three years, meaning the company needs significantly more working capital to support the same revenue. This trend is consuming cash that would otherwise be available for debt service.
The buyer adjusts the valuation downward to account for the incremental working capital investment needed and builds an operational improvement plan focused on tightening collections and rationalizing inventory.
Composite example based on typical PE due diligence findings
| Metric | Formula | What It Measures | |
|---|---|---|---|
| DSO | (Accounts Receivable / Revenue) x 365 | How quickly customers pay; lower is better | |
| DIO | (Inventory / COGS) x 365 | How long inventory sits before sale; lower is better | |
| DPO | (Accounts Payable / COGS) x 365 | How long the company takes to pay suppliers; higher preserves cash | |
| CCC | DSO + DIO - DPO | Total days cash is tied up in operations; lower (or negative) is better |
Quiz: Working Capital Analysis
6 questions · ~3 min