Free cash flow remains significantly pressured, recording a -$814.6M outflow in 2026Q1, largely driven by a $730.1M negative swing in working capital.
| 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 | Dec'04 | Dec'03 | Dec'02 | Dec'01 | Dec'00 | Dec'99 | Dec'98 | Dec'97 | Dec'96 |
|---|
| Cash from Operations | -910.63M | -268.58M | -500.95M | -307.51M | -274.37M | 30.8M | 35.89M | 345.72M | 602.89M | 174.15M | -112.11M | 21.13M | 6.29M | 63.49M | 1.88M | -114.8M | -63.59M | -108.44M | 212.03M | 36.09M | -53.23M | -61.74M | -101.75M | -95.47M | -94.38M | -6.16M | -23.19M | -48.4M | -34.7M | -20.6M | -21.2M |
| Operating CF Margin % | - | -28.45% | -71.04% | -39.04% | -46.71% | 3.8% | 4.92% | 30.8% | 100.54% | 33.87% | -30.07% | 7.45% | 2.93% | 43.11% | 1.84% | -115.86% | -58.63% | -89.18% | 197.81% | 61.86% | -358.2% | -153.84% | -238.72% | -190.99% | -117.71% | -11.56% | -62.24% | -142.77% | -88.52% | -63% | -93.39% |
| Operating CF Growth % | -232.46% | 46.38% | -62.9% | -12.08% | -990.84% | -14.19% | -89.62% | -42.66% | 246.19% | 255.34% | -630.67% | 236.12% | -90.1% | 3284.49% | 101.63% | -80.52% | 41.36% | -151.14% | 487.44% | 167.81% | 13.79% | 39.32% | -6.57% | -1.16% | -1432.66% | 73.44% | 52.09% | -39.48% | -68.45% | 2.83% | -40.4% |
| Net Income | -326.58M | -381.39M | -453.9M | -366.29M | -269.72M | -28.6M | -486.77M | 303.26M | 214.99M | -17.3M | -86.56M | -88.28M | -38.98M | -60.64M | -65.48M | -84.8M | -61.25M | 150.67M | -11.96M | -10.99M | -45.9M | -72.4M | -142.5M | -95M | -72.24M | -73.83M | -53.48M | -59.2M | -43M | -31.1M | -26.5M |
| Depreciation & Amortization | 31.43M | 22.69M | 19.65M | 22.5M | 22.11M | 19.56M | 17.16M | 15.99M | 12.53M | 8.35M | 9.03M | 10.24M | 9.4M | 9.78M | 10.76M | 11.78M | 9.18M | 11.33M | 6.82M | 6.76M | 7.22M | 9.69M | 12.17M | 12.25M | 10.3M | 6.97M | 5.54M | 5.2M | 4.3M | 3.2M | 2.6M |
| Stock-Based Compensation | 104.11M | 0 | 130.2M | 105.81M | 100.26M | 120.68M | 230.12M | 146.57M | 131.31M | 85.97M | 72.11M | 59.31M | 31.38M | 11.42M | 8.57M | 9.85M | 12.16M | 13.38M | 15.06M | 9.91M | 5.75M | -544K | 913K | 0 | -3M | 4.57M | 0 | 0 | 0 | 0 | 0 |
| Deferred Taxes | 0 | 0 | 0 | 0 | 0 | 25.31M | 313.27M | -7.1M | -290.52M | 14.07M | 10.74M | -12.47M | -12.84M | -5.91M | -9.11M | 13.84M | 16.25M | 5.25M | -26.26M | -37.21M | -31.03M | 544K | -913K | 0 | 3M | -4.57M | 0 | 0 | 0 | 0 | 0 |
| Other Non-Cash Items | -54.49M | 141.32M | 12.49M | 7.73M | -134.59M | 7.67M | 35.66M | 55.69M | 35.17M | 39.5M | 34.1M | 31.75M | 12.11M | 22.83M | 6.93M | 1.92M | 1.51M | -184.96M | 17.51M | 14.02M | 8.16M | 9.9M | 52.8M | 11.53M | -14.38M | 35.53M | 25.67M | 15.5M | 11.4M | 400K | -100K |
| Working Capital Changes | -665.09M | -51.22M | -209.39M | -77.26M | 7.57M | -113.82M | -73.56M | -168.71M | 499.41M | 43.56M | -151.53M | 20.57M | 5.21M | 86.03M | 50.21M | -67.39M | -41.44M | -104.12M | 210.86M | 53.6M | 2.59M | -8.93M | -24.22M | -24.26M | -18.06M | 25.18M | -908K | -9.9M | -7.4M | 6.9M | 2.8M |
| Change in Receivables | -101.56M | 26.13M | 5.59M | -72.06M | 36.36M | 5.05M | -22M | -44.18M | 514K | 15.72M | -89.36M | -14.12M | 9.77M | -4.98M | 3.42M | 2.95M | 4.71M | -16.84M | 2.91M | 1.18M | 1.9M | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Change in Inventory | 254K | -13.67M | -5.07M | -6.39M | 2.77M | -2.84M | -1.26M | -5.41M | 1.4M | -2.49M | -590K | -609K | 1.74M | -1.91M | -1.98M | -1.66M | 284K | -17K | -1.32M | -1.96M | 90K | 1.77M | -9.7M | -2.9M | -11.09M | 0 | 0 | 0 | 0 | 0 | 0 |
| Change in Payables | 36.63M | -15.36M | 15.99M | 8.12M | 1.09M | -6M | -2.75M | -16.34M | -655K | 1.78M | -10.68M | 9.21M | 4.82M | 66K | 1.29M | 875K | 1.32M | -3.65M | 962K | -794K | 1.21M | -4.87M | -1.8M | 0 | -2.15M | 3.8M | 0 | 0 | 0 | 0 | 0 |
| Cash from Investing | 88.58M | -277.78M | -134.03M | -214.13M | -262.64M | 194.91M | 274.48M | -41.27M | -929.56M | -358.29M | 56.6M | -60.05M | -82.85M | -255.73M | 18M | 110.9M | 23.69M | -212.29M | -234.25M | -55.64M | -32.61M | 540K | 83.73M | -15.12M | -60.37M | -143.49M | -95.38M | -7.9M | 9.1M | -15.2M | -11.3M |
| Capital Expenditures | -61.99M | -51.44M | -45.28M | -23.8M | -20.1M | -17.9M | -41.05M | -36.28M | -17.65M | -37.86M | -11.53M | -11.75M | -11.1M | -5.36M | -5.17M | -11M | -17.56M | -16.29M | -17.07M | -5.01M | -2.56M | -422K | -3.53M | -7.55M | -36.83M | -9.29M | -1.65M | -4.8M | -4.4M | -3.5M | -900K |
| CapEx % of Revenue | 5.86% | 5.45% | 6.42% | 3.02% | 3.42% | 2.21% | 5.63% | 3.23% | 2.94% | 7.36% | 3.09% | 4.14% | 5.18% | 3.64% | 5.07% | 11.1% | 16.18% | 13.4% | 15.92% | 8.59% | 17.2% | 1.05% | 8.27% | 15.11% | 45.94% | 17.43% | 4.43% | 14.16% | 11.22% | 10.7% | 3.96% |
| Acquisitions | 0 | 0 | 0 | 22K | 254.08M | 5.95M | 5.93M | 5.38M | 4.04M | 2.51M | 4.47M | 25.53M | 22.95M | 3.81M | -3M | 3.67M | 6.01M | 2.88M | 3.4M | -80.4M | 1.51M | 14.02M | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Investments | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
| Other Investing | -5.11M | -5.64M | -5.06M | -4.21M | 0 | -5.95M | -5.93M | -5.38M | -4.04M | -323.53M | 63.71M | -52.36M | -75.33M | -3.81M | 3M | -3.67M | -11.91M | -2.88M | -3.4M | -83.12M | -1.51M | 832K | -16.41M | -11.6M | -19.05M | -36.4M | -23.78M | -16.5M | -4M | -3.5M | -800K |
| Cash from Financing | 730.9M | 675.84M | 478.06M | 644.08M | -55.3M | 245.93M | -596.61M | 100.02M | 475.87M | 229.09M | 11.39M | 24.73M | 59.59M | 227.72M | 39.13M | -672K | 4.7M | 202M | 107.58M | 43.65M | 149.46M | 37.6M | 12.15M | 41.85M | 129.59M | 237.04M | 122.88M | 63.9M | 15.1M | 36.7M | 23M |
| Debt Issued (Net) | 483.23M | 483.24M | -44.67M | 86.9M | -50.69M | 313.57M | 0 | 97M | 0 | -23.98M | -3.07M | -558K | 35.05M | -8.53M | 29.66M | -4.24M | 340K | 3.57M | 4.81M | 22.3M | -7.85M | -11.57M | 8.1M | 40.15M | 129.59M | 26.58M | 4.64M | -400K | 11.2M | 36.7M | 23.1M |
| Equity Issued (Net) | 247.66M | 192.6M | 522.73M | 49.44M | 6.37M | 85.71M | -103.96M | 85.27M | 475.87M | 255.11M | 13.42M | 24.89M | 23.07M | 0 | 0 | 3.57M | 4.36M | 13.16M | 62.68M | 11.35M | 86.36M | 49.17M | 4.05M | 1.7M | 8.89M | 210.46M | 0 | 64.3M | 3.9M | 0 | 0 |
| Dividends Paid | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 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 | -90.55M | -34.39M | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Other Financing | 0 | 0 | 0 | 507.74M | -10.98M | -153.34M | -492.65M | -82.24M | 0 | -2.04M | 1.04M | 396K | 1.46M | 236.25M | 9.47M | 0 | 0 | 185.28M | 40.1M | 10M | 70.95M | 0 | 0 | 0 | -8.89M | 0 | 118.24M | 0 | 0 | 0 | -100K |
| Net Change in Cash | -90.81M | 130.18M | -157.19M | 122.79M | -592.72M | 471.53M | -285.62M | 404.47M | 149.19M | 44.95M | -44.11M | -14.2M | -16.98M | 35.49M | 59.01M | -4.58M | -35.2M | -118.73M | 85.37M | 24.1M | 63.63M | -23.6M | -5.87M | -68.74M | -25.16M | 87.4M | 4.32M | 7.7M | 15.1M | 36.7M | 23M |
| Free Cash Flow | -971.26M | -320.03M | -546.23M | -335.52M | -294.47M | 12.9M | -5.16M | 309.44M | 585.24M | 136.29M | -123.63M | 9.38M | -4.82M | 58.13M | -3.29M | -125.8M | -81.15M | -124.73M | 194.96M | 31.08M | -55.78M | -62.16M | -105.28M | -103.03M | -131.22M | -15.45M | -24.84M | -53.2M | -39.1M | -24.1M | -22.1M |
| FCF Margin % | -91.81% | -33.9% | -77.46% | -42.6% | -50.13% | 1.59% | -0.71% | 27.56% | 97.59% | 26.51% | -33.17% | 3.31% | -2.25% | 39.47% | -3.23% | -126.96% | -74.81% | -102.58% | 181.89% | 53.28% | -375.4% | -154.89% | -246.99% | -206.1% | -163.65% | -28.99% | -66.66% | -156.93% | -99.74% | -73.7% | -97.36% |
| FCF Growth % | -70.64% | 41.41% | -62.8% | -13.94% | -2383.06% | 350.16% | -101.67% | -47.13% | 329.4% | 210.24% | -1418.47% | 294.58% | -108.29% | 1864.75% | 97.38% | -55.02% | 34.94% | -163.98% | 527.22% | 155.73% | 10.27% | 40.95% | -2.18% | 21.48% | -749.56% | 37.81% | 53.32% | -36.06% | -62.24% | -9.05% | -36.42% |
| FCF per Share | -5.89 | -2.00 | -3.65 | -2.34 | -2.08 | 0.09 | -0.04 | 2.17 | 4.37 | 1.08 | -1.02 | 0.08 | -0.04 | 0.53 | -0.03 | -1.26 | -0.82 | -1.27 | 2.06 | 0.37 | -0.75 | -0.99 | -1.86 | -1.86 | -2.41 | -0.35 | -0.67 | -1.85 | -1.45 | -0.91 | -0.87 |
| FCF Conversion (FCF/Net Income) | 2.97x | 0.70x | 1.10x | 0.84x | 1.02x | -1.08x | -0.08x | 1.24x | 2.20x | 503.32x | 1.86x | -0.24x | -0.16x | -1.05x | -0.03x | 1.35x | 1.04x | -0.70x | -11.67x | -3.28x | 1.16x | 0.85x | 0.71x | 1.01x | 1.31x | 0.08x | 0.43x | 0.82x | 0.81x | 0.66x | 0.80x |
| Interest Paid | 5.31M | 0 | 0 | 6.51M | 2.9M | 4.78M | 6.25M | 9.87M | 0 | 0 | 0 | 0 | 0 | 6M | 0 | 4.8M | 4.89M | 4.88M | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Taxes Paid | 371K | 0 | 0 | 48.33M | 5.01M | 38K | 25.86M | 9.04M | 0 | 0 | 0 | 0 | 0 | 2K | 0 | 2K | 7.27M | 13.21M | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Commercialization execution and dilution
As reported in recent financial filings, the relationship between net income and operating cash flow remains highly erratic, with the 2026Q1 period showing an OCF/NI ratio of 8.57, suggesting that non-cash items and working capital swings significantly distort the underlying quality of reported earnings.
The extreme variance in the OCF/NI ratio indicates that net income is a poor proxy for the company's actual cash-generating capacity. Investors should monitor whether this divergence is a temporary byproduct of milestone-based revenue recognition or a structural issue inherent in the transition to a commercial-stage entity.
Based on the provided cash flow data, Ionis recorded a free cash flow of -$814.6M in 2026Q1, reflecting a persistent and widening cash burn that highlights the significant capital intensity required to support the company's current R&D and commercialization efforts as it pivots away from licensing.
The trajectory of free cash flow suggests that the company is currently in a high-expenditure phase that is not yet offset by commercial product sales. This trend warrants further investigation into the sustainability of the current burn rate without additional non-dilutive financing or milestone payments.
According to the quarterly cash flow statements, Ionis experienced a substantial working capital outflow of $730.1M in 2026Q1, which appears to be the primary driver of the quarter's significant cash depletion and underscores the volatility inherent in the company's current operational and revenue cycle.
Such large fluctuations in working capital suggest that the timing of milestone payments and the buildup of commercial inventory are creating significant liquidity pressure. Analysts should interpret these swings as a potential indicator of operational friction as the company scales its internal commercial infrastructure.
As indicated by the historical data, Ionis has maintained a relatively consistent capital expenditure profile, with CapEx/Revenue ratios reaching as high as 11.3% in 2024Q4, signaling that the company is actively investing in the physical and technical assets necessary to support its independent commercialization strategy.
While these expenditures are necessary for the transition to a self-commercializing pharma company, they represent a permanent increase in the cost base. The market should monitor whether these investments yield the expected operating leverage or if they will continue to weigh on free cash flow margins.
Quick answers to the most common questions about buying IONS stock.
Ionis Pharmaceuticals, Inc. (IONS) generated $-268.6M in net cash from operating activities in 2025. This reflects the cash generated directly from core business operations.
Ionis Pharmaceuticals, Inc. (IONS) reported negative free cash flow of $320.0M in 2025, indicating capital requirements exceeded cash from operations.
Ionis Pharmaceuticals, Inc. (IONS) spent $51.4M on capital expenditures in 2025. CapEx represents the cash invested in physical assets like property, plant, and equipment to maintain or grow the business.