Persistent negative free cash flow remains a primary concern, with quarterly outflows reaching as high as $10.8 million in 2024Q1, reflecting the intensive capital demands of late-stage clinical development.
| 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 |
|---|
| Cash from Operations | -28.16M | -28.39M | -35.4M | -31.41M | -23.81M | -26.02M | -10.42M | -17.64M | -30.42M | -10.99M | -44.91M | -48.16M | -42.87M | -28.91M | -20.96M | -14.67M | -10.26M | -11.77M | -9.43M | -6.05M | -2.11M |
| Operating CF Margin % | - | - | - | - | -2380.9% | -342.38% | -548.26% | - | - | - | - | - | -460.02% | -1162.36% | -1028.61% | - | - | - | - | - | - |
| Operating CF Growth % | 67.42% | 19.81% | -12.71% | -31.92% | 8.5% | -149.79% | 40.96% | 42.01% | -176.84% | 75.53% | 6.74% | -12.34% | -48.29% | -37.9% | -42.92% | -43% | 12.85% | -24.82% | -55.93% | -186.32% | - |
| Net Income | -29.46M | -26.86M | -30.88M | -37.34M | -41.3M | -20.7M | -16.76M | -19.29M | -27.67M | -23.75M | -11.1M | -38.96M | -36.61M | -76.68M | -34.97M | -11.48M | -11.99M | -18.39M | -14.37M | -10.99M | -2.4M |
| Depreciation & Amortization | 0 | 0 | 0 | 0 | 457K | 5.68M | 282K | 1.7M | 3.76M | 0 | 142K | 355K | 889K | 452K | 49K | 163K | 172K | 162K | 131K | 36K | 0 |
| Stock-Based Compensation | 1.45M | 1.96M | 1.56M | 1.39M | 1.73M | 1.01M | 578K | 573K | 395K | 3.17M | 2.26M | 1.93M | 5.39M | 2.53M | 1.39M | 3M | 4.37M | 4.2M | 3.82M | 0 | 0 |
| Deferred Taxes | 0 | 0 | 0 | 0 | -457K | -239K | -23K | -95K | -1.32M | 0 | 243K | 365K | -16.36M | 1.05M | -1.05M | 12.39M | 0 | 4K | 0 | 0 | 0 |
| Other Non-Cash Items | 1.4M | 597K | 561K | 1.2M | 10.13M | -4.16M | -87K | 586K | 4.42M | 3.53M | -11.55M | -31.73M | -170K | 41.23M | 13.51M | -21.29M | -3.12M | 1.97M | 994K | 4.23M | 474K |
| Working Capital Changes | -1.56M | -4.08M | -6.65M | 3.35M | 5.64M | -7.62M | 5.59M | -1.11M | -10.01M | 6.07M | -24.91M | 19.87M | 3.99M | 2.51M | 106K | 2.56M | 312K | 285K | -5K | 674K | -181K |
| Change in Receivables | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 21.7M | 0 | 1.64M | -3.68M | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Change in Inventory | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | -269K | -386K | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Change in Payables | -127K | -535K | -2.14M | 2.3M | 1.21M | -2.51M | -836K | 12K | -7.94M | 8.37M | -757K | -289K | -389K | 684K | 641K | 500K | 99K | 231K | 339K | -79K | 0 |
| Cash from Investing | 0 | 0 | 0 | -5.5M | -4.5M | 0 | 0 | 0 | 0 | 1.81M | -1.06M | 10.39M | -5.53M | -12.04M | -87K | 14K | -106K | -83K | 9.6M | -10.03M | 0 |
| Capital Expenditures | 0 | 0 | 0 | -5.5M | -4.5M | 0 | 0 | 0 | 0 | 0 | -6K | -153K | -5.53M | -15.85M | 0 | -53K | -106K | -83K | -166K | -229K | 0 |
| CapEx % of Revenue | - | - | - | - | 450% | - | - | - | - | - | - | - | 59.32% | 637.23% | - | - | - | - | - | - | - |
| Acquisitions | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1.81M | 0 | 0 | 0 | 0 | -87K | 168K | 106K | 0 | 0 | 0 | 0 |
| Investments | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
| Other Investing | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | -1.05M | 10.55M | -5.53M | -99K | -87K | -101K | -106K | 0 | 21K | -16K | 0 |
| Cash from Financing | 106.86M | 86.3M | 46.76M | 22.32M | 24.08M | 12.07M | 38.44M | 19.57M | 23.12M | 5.53M | 34.32M | 43.84M | 24.26M | 55.92M | 42.42M | 19.2M | 11.57M | 7.68M | 7.92M | 17.83M | 2.11M |
| Debt Issued (Net) | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | -7.6M | -473K | 16.5M | -3.91M | -1.77M | 9.87M | 500K | 416K | -70K | -34K | -22K | 0 | 0 |
| Equity Issued (Net) | 107.39M | 86.82M | 46.16M | 22.23M | 23.99M | 9.01M | 29.6M | 15.97M | 31.21M | 6.01M | 0 | 47.73M | 10.97M | 37.7M | 36.47M | 18.63M | 11.39M | 7.71M | 7.92M | 15.83M | 0 |
| Dividends Paid | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | -487K | -675K | 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 | 0 | 0 | 0 | 0 | -3.85M | 0 | 0 | 0 | 0 |
| Other Financing | -527K | -527K | 594K | 90K | 85K | 3.07M | 8.84M | 3.6M | 0 | 0 | 0 | 31K | 15.06M | 8.36M | 5.45M | 150K | 254K | 0 | 26K | 2M | 2.11M |
| Net Change in Cash | 78.7M | 57.91M | 11.36M | -14.6M | -4.23M | -13.95M | 28.02M | 1.93M | -7.3M | -3.64M | -11.65M | 6.08M | -24.14M | 14.98M | 21.37M | 4.54M | 1.21M | -4.17M | 8.09M | 1.76M | 0 |
| Free Cash Flow | -28.16M | -28.39M | -35.4M | -36.91M | -28.31M | -26.02M | -10.42M | -17.64M | -30.42M | -10.99M | -44.92M | -48.31M | -48.4M | -44.76M | -20.96M | -14.72M | -10.36M | -11.85M | -9.6M | -6.28M | -2.11M |
| FCF Margin % | - | - | - | - | -2830.9% | -342.38% | -548.26% | - | - | - | - | - | -519.34% | -1799.6% | -1028.61% | - | - | - | - | - | - |
| FCF Growth % | 16.45% | 19.81% | 4.09% | -30.38% | -8.79% | -149.79% | 40.96% | 42.01% | -176.84% | 75.54% | 7.02% | 0.17% | -8.14% | -113.5% | -42.4% | -42.05% | 12.56% | -23.52% | -52.88% | -197.16% | - |
| FCF per Share | -0.16 | -0.26 | -0.58 | -1.33 | -1.46 | -1.68 | -1.31 | -6.90 | -116.32 | -234.77 | -2370.75 | -2415.65 | -1351.46 | -1654.32 | -1118.74 | -1350.67 | -1881.45 | -2438.68 | -2327.75 | -1652.45 | -558.73 |
| FCF Conversion (FCF/Net Income) | 0.96x | 1.06x | 1.15x | 0.84x | 0.58x | 1.26x | 0.62x | 0.91x | 1.10x | 0.46x | 1.91x | 0.75x | 1.17x | 0.38x | 0.60x | 1.28x | 0.86x | 0.64x | 0.66x | 0.55x | 0.88x |
| Interest Paid | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Taxes Paid | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 7K | 0 | 0 |
Binary clinical trial failure
As reported in financial statements, SELLAS Life Sciences consistently records operating cash outflows that exceed net losses, with the OCF/NI ratio reaching as high as 1.56 in 2025Q1, indicating that non-cash adjustments and working capital movements are failing to bridge the gap between accounting losses and cash reality.
The persistent divergence between net income and operating cash flow suggests that the company's cash burn is driven by core operational requirements rather than non-cash accounting charges. Investors should monitor this relationship, as the inability to align cash outflows with reported losses may imply that the firm's underlying cost structure is more volatile than the income statement suggests.
Based on the provided quarterly data, the company has maintained a consistent negative free cash flow trajectory, with quarterly outflows ranging from $4.8 million to $10.8 million, reflecting the heavy capital requirements inherent in late-stage clinical development and the absence of any offsetting commercial revenue streams.
The lack of positive free cash flow is characteristic of a pre-revenue biotech firm, yet the magnitude of these outflows warrants close scrutiny as the company approaches critical data readouts. This trend suggests that the firm remains entirely dependent on external financing to sustain its research activities, leaving it vulnerable to shifts in capital market sentiment.
According to recent SEC filings, working capital changes have fluctuated significantly, swinging from a $3.9 million outflow in 2025Q1 to a $2.1 million inflow in 2025Q4, which highlights the unpredictable nature of cash management in a firm that lacks a stable, recurring revenue-generating operational cycle.
These fluctuations appear to be driven by the timing of clinical trial payments and vendor obligations rather than operational efficiency. The inconsistency in working capital movements suggests that liquidity management is highly reactive, which may complicate the company's ability to forecast its cash runway with precision during the final stages of the REGAL trial.
Based on reported figures, stock-based compensation has consistently added back to the cash flow statement, with quarterly amounts reaching up to $505,000, which effectively obscures the true economic cost of talent retention and management incentives during this high-risk, pre-revenue phase of the company's development.
While these non-cash charges are standard in the biotech sector, they represent a form of dilution that is not fully captured by the cash flow statement alone. Analysts should consider that the actual cost of operations is higher than the reported cash burn, as the reliance on equity-based compensation serves as a proxy for cash that would otherwise be required to attract specialized personnel.
Quick answers to the most common questions about buying SLS stock.
SELLAS Life Sciences Group, Inc. (SLS) generated $-28.4M in net cash from operating activities in 2025. This reflects the cash generated directly from core business operations.
SELLAS Life Sciences Group, Inc. (SLS) reported negative free cash flow of $28.4M in 2025, indicating capital requirements exceeded cash from operations.
SELLAS Life Sciences Group, Inc. (SLS) 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.