Liquidity remains highly sensitive to working capital fluctuations, as demonstrated by a $41.1 million cash outflow in 2025Q4 followed by a $21.7 million inflow in 2026Q1.
| Cash from Operations | 7.24M | -12.62M | -23.44M | -32.99M | -7.73M | -64.35M | -85.87M | -50.02M | -39.63M | -39.11M | -28.96M | -9.61M |
| Operating CF Margin % | - | -21.17% | -48.87% | -31.79% | -15.91% | -2095.99% | -920.39% | -275.64% | -999.12% | -1976.3% | -8644.48% | - |
| Operating CF Growth % | 602.83% | 46.15% | 28.95% | -326.79% | 87.99% | 25.07% | -71.68% | -26.23% | -1.31% | -35.06% | -201.41% | - |
| Net Income | 15.23M | 8.57M | -68.57M | 22.81M | -46.41M | -89.76M | -78.28M | -60.92M | -41.66M | -39.89M | -32.64M | -13.15M |
| Depreciation & Amortization | 0 | 0 | 2K | 367K | 1.55M | 1.12M | 761K | 750K | 409K | 363K | 279K | 11K |
| Stock-Based Compensation | 2.77M | 4.33M | 7.79M | 7.93M | 0 | 0 | 4.89M | 3.78M | 2.75M | 1.43M | 180K | 21K |
| Deferred Taxes | 0 | 0 | 0 | 0 | 0 | 0 | 0 | -808K | 0 | 83K | -580K | -174K |
| Other Non-Cash Items | 2.7M | 1.64M | 1.04M | 6.28M | 15.05M | 11.43M | 151K | 356K | -50K | -1.54M | 4.59M | 3.52M |
| Working Capital Changes | -13.46M | -27.16M | 36.28M | -70.38M | 22.09M | 12.86M | -13.39M | 6.83M | -1.07M | 443K | -792K | 170K |
| Change in Receivables | 25.98M | 3.06M | -1.54M | -461K | 1.55M | 3.83M | 2.18M | -7.08M | 1.41M | -2.52M | -294K | -10K |
| Change in Inventory | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 7.08M | 0 | 0 | 0 | 0 |
| Change in Payables | -1.55M | -6.61M | 5.93M | 761K | -484K | -53K | -2.98M | 564K | 84K | 2.35M | -644K | 671K |
| Cash from Investing | 0 | 0 | 0 | 0 | 33.81M | 7.67M | 10.47M | 29.53M | -83.16M | -27K | -830K | -232K |
| Capital Expenditures | 0 | 0 | 0 | 0 | 0 | 0 | -157K | -314K | -2.44M | -27K | -830K | -232K |
| CapEx % of Revenue | 0% | - | - | - | - | 2095.99% | 1.68% | 1.73% | 61.42% | 1.36% | 247.76% | - |
| Acquisitions | 0 | 0 | 0 | 0 | 0 | 39K | 0 | -29.84M | 83.16M | -1.18M | 0 | 0 |
| Investments | - | - | - | - | - | - | - | - | - | - | - | - |
| Other Investing | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 29.84M | -83.16M | -27K | 0 | 0 |
| Cash from Financing | 0 | 0 | 0 | 221K | -29.55M | 84.05M | 130.88M | 16.14M | 69.52M | 116.11M | 34.41M | 15.28M |
| Debt Issued (Net) | 0 | 0 | 0 | 0 | -54.48M | 47.48M | 0 | 0 | 0 | 0 | 0 | 0 |
| Equity Issued (Net) | 0 | 0 | 0 | 221K | 24.93M | 36.57M | 129.65M | 15.79M | 70.5M | 120.86M | 25.91M | 7.33M |
| Dividends Paid | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Share Repurchases | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Other Financing | 0 | 0 | 0 | 0 | 0 | 0 | 1.24M | 350K | -977K | -4.75M | 8.5M | 7.95M |
| Net Change in Cash | 7.24M | -12.62M | -23.44M | -32.77M | -3.48M | 27.38M | 55.48M | -4.35M | -53.26M | 76.97M | 4.62M | 5.43M |
| Free Cash Flow | 7.24M | -12.62M | -23.44M | -32.99M | -7.73M | 0 | -86.03M | -50.33M | -42.06M | -39.14M | -29.79M | -9.84M |
| FCF Margin % | 13.22% | -21.17% | -48.87% | -31.79% | -15.91% | - | -922.07% | -277.37% | -1060.54% | -1977.67% | -8892.24% | - |
| FCF Growth % | 121.69% | 46.15% | 28.95% | -326.79% | - | 100% | -70.92% | -19.67% | -7.47% | -31.38% | -202.73% | - |
| FCF per Share | 0.13 | -0.21 | -0.43 | -0.62 | -0.21 | - | -3.84 | -2.77 | -2.63 | -15.13 | -4.51 | -1.49 |
| FCF Conversion (FCF/Net Income) | 0.48x | -1.47x | 0.34x | -1.45x | 0.17x | 0.72x | 1.10x | 0.82x | 0.95x | 0.85x | 1.14x | 0.95x |
| Interest Paid | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Taxes Paid | 0 | 0 | 99K | 2.21M | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Binary Clinical Trial Dependency
As reported in financial statements, Spero’s operating cash flow frequently diverges from net income, with OCF/NI ratios swinging from -2.20 in 2026Q1 to 10.41 in 2025Q2, illustrating that accounting earnings provide little insight into the company's actual liquidity position or its ability to generate cash.
The extreme volatility in the OCF/NI ratio suggests that net income is heavily influenced by non-cash accounting adjustments and the timing of milestone revenue recognition. Investors should monitor this divergence as a signal that the company's reported profitability is not indicative of operational cash generation, but rather a byproduct of its transactional licensing model.
Based on reported figures, Spero’s free cash flow trajectory is highly erratic, oscillating between positive inflows of $17.4 million in 2025Q3 and significant outflows of $23.4 million in 2024Q4, reflecting a business model entirely dependent on the timing of non-recurring collaboration milestone payments.
The lack of consistent FCF generation highlights the company's status as a pre-commercial entity that relies on external capital injections to sustain its R&D burn. This trajectory suggests that the company remains in a high-risk phase where cash flow sustainability is contingent upon successful clinical outcomes rather than operational efficiency.
According to recent SEC filings, Spero’s cash flow is heavily impacted by working capital fluctuations, evidenced by a $41.1 million outflow in 2025Q4 followed by a $21.7 million inflow in 2026Q1, which underscores the sensitivity of the company's liquidity to the timing of partner-related payments.
These large swings in working capital appear to be driven by the accumulation and subsequent settlement of deferred revenue and milestone-related receivables. This pattern warrants further investigation, as it suggests that the company's cash position is subject to significant quarter-to-quarter variability that may not reflect underlying operational health.
Based on the provided cash flow data, the company’s reliance on milestone-driven inflows obscures the underlying cash burn, as evidenced by the fact that operating cash flow is frequently bolstered by working capital movements rather than sustainable, recurring revenue streams from its core clinical programs.
The absence of meaningful capital expenditures suggests that the company is not currently investing in physical infrastructure, but rather focusing its limited resources on clinical trial execution. Investors should be cautious, as the current cash flow profile may mask the true cost of maintaining the R&D pipeline in the absence of future milestone receipts.
Quick answers to the most common questions about buying SPRO stock.
Spero Therapeutics, Inc. (SPRO) generated $-12.6M in net cash from operating activities in 2025. This reflects the cash generated directly from core business operations.
Spero Therapeutics, Inc. (SPRO) reported negative free cash flow of $12.6M in 2025, indicating capital requirements exceeded cash from operations.
Spero Therapeutics, Inc. (SPRO) spent $0.0M on capital expenditures in 2025. CapEx represents the cash invested in physical assets like property, plant, and equipment to maintain or grow the business.