Free cash flow remains deeply negative with quarterly outflows frequently exceeding $15 million, while stock-based compensation of $4.9 million in 2025Q4 masks the true economic cost of operations.
| Metric | TTM | Dec'25 | Dec'24 | Dec'23 | Dec'22 | Dec'21 | Dec'20 | Dec'19 | Dec'18 | Dec'17 | Dec'16 | Dec'15 | Dec'14 | Dec'13 | Dec'12 | Dec'11 | Dec'10 | Dec'09 | Dec'08 | Dec'07 | Dec'06 | Dec'05 |
|---|
| Cash from Operations | -71.94M | -67.53M | -79.85M | -75.81M | -62.59M | -78.24M | -34.31M | -9.6M | -9.39M | -20.21M | 201.51M | -3.22M | -8.47M | -7.17M | -2.32M | -7.81M | -14.86M | -28.15M | -13.2M | -13.64M | 1.53M | 554.33K |
| Operating CF Margin % | - | -164719.51% | -399240% | -17795.77% | 92038.24% | -1774.1% | -419.13% | -165.51% | -90.88% | -48705.1% | 3852.79% | -30.22% | -83.16% | -40.02% | -9.23% | -32.18% | -70.81% | -102.16% | -40.1% | -93.12% | 82.72% | 94.58% |
| Operating CF Growth % | 16.79% | 15.42% | -5.33% | -21.13% | 20.01% | -128.06% | -257.28% | -2.27% | 53.55% | -110.03% | 6365.84% | 62.05% | -18.22% | -208.59% | 70.25% | 47.47% | 47.19% | -113.25% | 3.21% | -992.21% | 175.72% | - |
| Net Income | -91.08M | -88.09M | -95.06M | -88.45M | -84.71M | -97.09M | -49.04M | -20.52M | -39.17M | -46.43M | 193.85M | -3.44M | -9.96M | -11.72M | -4.92M | -3.8M | -34.85M | -32.28M | -36.42M | -13.59M | 1.02M | 277.3K |
| Depreciation & Amortization | 106K | 112K | 238K | 477K | 493K | 551K | 428.88K | 387.32K | 302.37K | 139.02K | 143.44K | 141.6K | 149.96K | 182.49K | 303.92K | 461.07K | 1.02M | 872.3K | 813.89K | 655.21K | 0 | 0 |
| Stock-Based Compensation | 8.49M | 16.08M | 14.39M | 10.64M | 8.1M | 5.52M | 2.58M | 0 | 773.25K | 1.44M | 2.24M | 613.02K | 1.66M | 1.36M | 1.89M | 2.57M | 2.51M | 3.44M | 3.04M | 0 | 0 | 0 |
| Deferred Taxes | 0 | -681K | 0 | 0 | 0 | 0 | 0 | -58.5K | -6.15M | -2.62B | 61.82K | 61.75K | 61.75K | 61.75K | 195.53K | 2.98M | 0 | 0 | 0 | 0 | 0 | 0 |
| Other Non-Cash Items | 5.86M | -1.7M | -3.9M | 9.79M | -578K | 13.03M | 16.25M | 8.77M | 27.88M | 2.65B | 1.01M | -86.26K | -431.19K | 576.28K | -1.76M | -10.94M | 17.68M | 5.28M | 17.77M | -885.84K | 0 | 0 |
| Working Capital Changes | 4.69M | 6.75M | 4.48M | -8.27M | 14.11M | -251K | -4.51M | 1.82M | 6.98M | -11.31M | 4.2M | -505.38K | 45.19K | 2.37M | 1.97M | 929.25K | -1.23M | -5.46M | 1.59M | 181.22K | 512.09K | 277.04K |
| Change in Receivables | 799K | 2.06M | 1.74M | -2.31M | 3.3M | 6.53M | -10.72M | 2.82M | 344.3K | -1.95M | 476.19K | -1.07M | 3.22M | 2.92M | 898.57K | 1.2M | 1.83M | -4.9M | -2.2M | -3.63M | 0 | 0 |
| Change in Inventory | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 5.59M | -4.12M | 3.27M | -14.62M | -2.09M | 1.06M | -50.93K | -13.58M | -21.73M | -9.38M | -6.42M | 3.22M | 0 | 0 |
| Change in Payables | 453K | 2.51M | -1.86M | -2.73M | 2.77M | 1.42M | 594.06K | -354.63K | 243.06K | -2.62M | 405.41K | 129.73K | -736.78K | -569.12K | 251.56K | -1.68M | 1.25M | -1.94M | -60.7K | 564.43K | 0 | 0 |
| Cash from Investing | -131.06M | -132.47M | -28.39M | 13.73M | -73.4M | 87.52M | -72.23M | -28.29M | -1M | 13.73M | -66.88M | -78.91K | -84.27K | -81.08K | 67.4K | 1.69M | 2.76M | -7.99M | -10.1M | -12.94M | -2.25M | -68.64M |
| Capital Expenditures | -32K | -11K | 0 | -47K | -126K | -12.12M | -203.96K | -29K | -1.02M | -166.33K | -30.69K | -86.51K | -92.27K | -84.58K | 0 | -71.44K | -374.58K | -1.03M | -509.31K | -882.35K | 0 | 0 |
| CapEx % of Revenue | 88.89% | 26.83% | - | 11.03% | -185.29% | 274.76% | 2.49% | 0.5% | 9.83% | 400.76% | 0.59% | 0.81% | 0.91% | 0.47% | - | 0.29% | 1.78% | 3.74% | 1.55% | 6.03% | - | - |
| Acquisitions | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 14.49K | 13.68M | 0 | 7.6K | 0 | 0 | 0 | 0 | 0 | -7M | -11.56M | 0 | 0 | 0 |
| Investments | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
| Other Investing | 0 | 0 | 0 | 0 | 0 | -195K | -138.46K | 0 | 14.49K | 207.63K | 687 | 7.6K | 8K | 3.5K | 67.4K | 1.76M | 0 | 0 | -7M | 0 | -2.25M | -68.64M |
| Cash from Financing | 251.49M | 206.84M | 10.04M | 86.11M | 56.78M | 65.1M | 213.49M | 12.53M | 32.49M | 15.84M | 3.8M | 223.13K | 16.73M | 5.03M | 3.72M | 5.78M | 21.46M | 18.79M | 2.41M | 61.93M | 0 | 69.48M |
| Debt Issued (Net) | 34.25M | 33.92M | 0 | 0 | 0 | 0 | 0 | -292K | -1.55M | 2.81M | -80.57K | -750.01K | -2.09M | -988.76K | 3.83M | 0 | -11.44K | 990.18K | -4M | 8.71M | 11.77M | 0 |
| Equity Issued (Net) | 217.97M | 173.63M | 9.99M | 86.6M | 56.35M | 65.04M | 172.32M | 12.7M | 35.02M | 13.02M | 5.67M | 973.13K | 18.14M | 6.02M | 38.98K | 5.86M | 21.57M | 4.95M | 12.66M | 57.91M | 245.79K | 69.48M |
| Dividends Paid | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Share Repurchases | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | -2.39M | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 57.91M | 0 | -5.75M |
| Other Financing | -717K | -709K | 50K | -496K | 434K | 58K | 41.17M | 125K | -977.1K | 16.45K | -611.65K | 0 | 683.33K | 0 | -149.42K | -74.36K | -100K | 12.85M | -6.25M | -4.69M | 0 | 0 |
| Net Change in Cash | 48.5M | 6.83M | -98.19M | 24.03M | -79.2M | 74.38M | 106.96M | -25.36M | 22.05M | 9.43M | 138.43M | -3.07M | 8.16M | -2.22M | 1.46M | -548.56K | 9.11M | -17.08M | -20.83M | 35.47M | -722.88K | 1.4M |
| Free Cash Flow | -71.97M | -67.55M | -79.85M | -75.86M | -62.71M | -90.55M | -34.65M | -9.6M | -10.4M | -20.38M | 201.48M | -3.3M | -8.57M | -7.25M | -2.32M | -7.88M | -15.24M | -29.18M | -13.71M | -14.52M | 1.53M | 554.33K |
| FCF Margin % | -199908.33% | -164746.34% | -399240% | -17806.81% | 92223.53% | -2053.29% | -423.31% | -165.53% | -100.71% | -49105.86% | 3852.2% | -31.04% | -84.06% | -40.49% | -9.23% | -32.47% | -72.59% | -105.9% | -41.65% | -99.15% | 82.72% | 94.58% |
| FCF Growth % | 10.41% | 15.41% | -5.26% | -20.96% | 30.74% | -161.34% | -260.8% | 7.7% | 48.95% | -110.12% | 6200.78% | 61.45% | -18.11% | -212.23% | 70.52% | 48.29% | 47.77% | -112.83% | 5.59% | -1049.94% | 175.72% | - |
| FCF per Share | -0.58 | -0.77 | -1.12 | -1.42 | -1.34 | -2.19 | -1.35 | -0.73 | -3.71 | -47.75 | 874.54 | -15.48 | -44.67 | -42.95 | -14.42 | -49.95 | -141.50 | -317.41 | -179.24 | -461.29 | 32.65 | 19.98 |
| FCF Conversion (FCF/Net Income) | 0.79x | 0.77x | 0.84x | 0.86x | 0.74x | 0.81x | 0.70x | 0.47x | 0.24x | 0.44x | 1.04x | 0.93x | 0.85x | 0.61x | 0.47x | 2.06x | 0.43x | 0.87x | 0.36x | 1.00x | 1.50x | 2.00x |
| Interest Paid | 381K | 0 | 0 | 0 | 0 | 0 | 1.79K | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 54.57K | 0 | 1.36M | 0 | 0 | 0 | 0 |
| Taxes Paid | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 10.63K | 0 | 184.23K | 0 | 0 | 0 | 0 |
Imminent dilutive capital raise
According to recent financial statements, Altimmune consistently reports operating cash outflows that closely track net losses, with the OCF/NI ratio fluctuating between 0.52 and 1.19, indicating that the company lacks any meaningful non-cash accruals to bridge the gap between accounting losses and actual cash depletion.
The tight correlation between net income and operating cash flow suggests that the company's burn is driven by real-time cash expenditures rather than accounting adjustments. Investors should monitor this relationship, as the absence of significant non-cash expenses implies that every dollar of reported loss translates directly into a reduction of the company's limited liquidity.
As reported in quarterly filings, the company's free cash flow remains deeply negative, with quarterly outflows frequently exceeding $15 million, which highlights the unsustainable nature of the current clinical development burn rate in the absence of any commercial revenue streams to offset these substantial R&D costs.
The persistent negative free cash flow trajectory underscores the company's total dependence on external financing to maintain its clinical pipeline. This trend appears to be accelerating as the company approaches later-stage trials, suggesting that the current cash runway is likely insufficient to reach commercialization without significant capital intervention.
Based on the provided cash flow data, working capital changes have been erratic, swinging from a $8.4 million outflow in 2024Q3 to a $3.6 million inflow in 2025Q4, which suggests that the timing of clinical trial payments and vendor accruals creates significant quarterly noise in cash balances.
This volatility in working capital appears to be a byproduct of the company's reliance on milestone-based clinical trial contracts. Analysts should interpret these fluctuations as temporary timing differences rather than structural improvements in cash management, as the underlying burn rate remains consistently high regardless of these periodic shifts.
As indicated by the cash flow statements, stock-based compensation (SBC) has consistently added back millions to the cash flow reconciliation, with figures reaching $4.9 million in 2025Q4, effectively masking the true economic cost of talent retention required to advance the company's complex metabolic therapeutic programs.
While SBC is a non-cash expense, it represents a significant dilution of shareholder value that is not fully captured by the operating cash flow metric. Investors should consider the impact of this ongoing equity issuance when evaluating the company's total cost of capital and the potential for future earnings per share dilution.
Quick answers to the most common questions about buying ALT stock.
Altimmune, Inc. (ALT) generated $-67.5M in net cash from operating activities in 2025. This reflects the cash generated directly from core business operations.
Altimmune, Inc. (ALT) reported negative free cash flow of $67.5M in 2025, indicating capital requirements exceeded cash from operations.
Altimmune, Inc. (ALT) 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.