Free cash flow has been negative in 8 of 10 quarters, averaging approximately -$16M per quarter during loss periods, with working capital swings of up to $91.2M (2024Q2 inflow) and -$24.2M (2024Q3 outflow) underscoring that reported accounting gains have not reliably translated into realized cash—cash conversion quality (OCF/NI) has ranged from -3.21 to 1.16, warranting careful due diligence into milestone collection timing.
AC Immune S.A. (ACIU) cash flow statement — 13-year operating, investing & financing cash flows
| 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 |
|---|
| Cash from Operations | -16.45M | -66.15M | 65.84M | -60.41M | -73.57M | -65.69M | -59.52M | 55.22M | -44.08M | -22.09M | -5.65M | 44.08M | -17.62M | -19.8M |
| Operating CF Margin % | - | -1851.33% | 241.1% | -408.13% | -1869.58% | - | -385.7% | 49.99% | -612.7% | -109.08% | -24.32% | 112.78% | -58.22% | -229.29% |
| Operating CF Growth % | -177.18% | -200.46% | 209% | 17.89% | -11.99% | -10.37% | -207.78% | 225.28% | -99.5% | -291.32% | -112.81% | 350.14% | 11.01% | - |
| Net Income | -36.05M | -67.28M | -50.92M | -54.23M | -70.75M | -73M | -61.92M | 45.44M | -50.95M | -26.41M | -7.1M | 20.27M | 10.74M | -11.24M |
| Depreciation & Amortization | 650.02K | 2.5M | 2.16M | 2.21M | 2.36M | 2.41M | 1.97M | 1.69M | 961K | 580K | 278K | 287K | 298K | 293K |
| Stock-Based Compensation | 2.63M | 0 | 5.47M | 4.37M | 3.33M | 4.13M | 4.09M | 2.83M | 2.52M | 1.58M | 1.32M | 540K | 210K | 256K |
| Deferred Taxes | 0 | 0 | 0 | 0 | 0 | 130K | 0 | 0 | 131K | 177K | -83K | 49K | 17K | 0 |
| Other Non-Cash Items | 15.32M | 5.1M | 1.61M | 2.4M | -72K | -6.2M | 922K | -400K | 1.45M | 3.97M | -3.36M | -1.65M | -27K | -9M |
| Working Capital Changes | -3.77M | -6.47M | 107.51M | -15.16M | -8.43M | 6.84M | -4.57M | 5.65M | 1.81M | -1.99M | 3.3M | 24.58M | -28.87M | -109K |
| Change in Receivables | 638.45K | 877.68K | 13.55M | -14.8M | 603K | -99K | -532K | 2.5M | 698K | -401K | -248K | 25.67M | -25.74M | 55K |
| Change in Inventory | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Change in Payables | 327.34K | -565.38K | 0 | 0 | 0 | 0 | 0 | 0 | 0 | -2.85M | 2.59M | -141K | 341K | 0 |
| Cash from Investing | 15.94M | 60.69M | -105.29M | 65.64M | 23.76M | -53.66M | 28.33M | -66.89M | -32.04M | -1.84M | -899K | -244K | -131K | -249K |
| Capital Expenditures | -107.17K | -859.54K | -576K | -801K | -1.24M | -2.63M | -1.71M | -1.89M | -1.86M | -1.8M | -899K | -244K | -128K | -249K |
| CapEx % of Revenue | 0.54% | 24.06% | 2.11% | 5.41% | 31.49% | - | 11.06% | 1.71% | 25.83% | 8.9% | 3.87% | 0.62% | 0.42% | 2.88% |
| Acquisitions | 19 | 14.32K | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Investments | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
| Other Investing | -211 | -162.36K | -104.71M | 66.45M | 25M | -51.03M | 30.04M | 0 | -178K | -40K | 0 | 0 | -3K | 0 |
| Cash from Financing | -259.95K | -974.14K | -1.12M | 43.25M | -1.35M | 40.75M | -803K | 49.62M | 109.38M | 271K | 78.79M | 27.78M | 9.8M | 10.01M |
| Debt Issued (Net) | -260K | -1.03M | -683K | -548K | -569K | 22.95M | -946K | 50.06M | 198K | 200K | 0 | 55K | 0 | 0 |
| Equity Issued (Net) | -983 | 5.73K | 111K | 43.8M | -1K | 17.8M | 0 | 0 | 111.53M | 0 | 82.89M | 29.5M | 10M | 0 |
| Dividends Paid | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Share Repurchases | 0 | 0 | 0 | 0 | -8K | 0 | -100K | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Other Financing | 1.03K | 46.13K | -548K | 0 | -776K | -6K | 143K | -441K | -2.35M | 71K | -4.11M | -1.78M | -199K | 10.01M |
| Net Change in Cash | -10.79M | -4.92M | -42.22M | 46.91M | -50.63M | -78.68M | -32.69M | 37.13M | 32.09M | -27.83M | 75.69M | 73.22M | -7.95M | -9.85M |
| Free Cash Flow | -16.55M | -67.01M | 65.27M | -61.21M | -74.81M | -68.32M | -61.22M | 53.34M | -45.94M | -23.9M | -6.54M | 43.84M | -17.75M | -20.05M |
| FCF Margin % | -83.55% | -1875.39% | 238.99% | -413.55% | -1901.07% | - | -396.75% | 48.29% | -638.53% | -117.98% | -28.19% | 112.15% | -58.65% | -232.18% |
| FCF Growth % | - | -202.67% | 206.63% | 18.18% | -9.49% | -11.6% | -214.79% | 216.11% | -92.23% | -265.1% | -114.93% | 346.96% | 11.47% | - |
| FCF per Share | -0.17 | -0.67 | 0.65 | -0.72 | -0.90 | -0.91 | -0.85 | 0.75 | -0.74 | -0.42 | -0.13 | 0.79 | -0.32 | -0.49 |
| FCF Conversion (FCF/Net Income) | 0.46x | 0.94x | -1.29x | 1.11x | 1.04x | 0.90x | 0.96x | 1.22x | 0.87x | 0.84x | 0.80x | 2.17x | -1.64x | 1.76x |
| Interest Paid | 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 |
Quick answers to the most common questions about buying ACIU stock.
AC Immune S.A. (ACIU) generated $-66.1M in net cash from operating activities in 2025. This reflects the cash generated directly from core business operations.
AC Immune S.A. (ACIU) reported negative free cash flow of $67.0M in 2025, indicating capital requirements exceeded cash from operations.
AC Immune S.A. (ACIU) spent $0.9M on capital expenditures in 2025. CapEx represents the cash invested in physical assets like property, plant, and equipment to maintain or grow the business.
Key Metrics
Top Statement Risk
Milestone-timing cash flow dependency
Earnings-to-Cash Conversion Highly Erratic
Cash conversion quality is highly erratic, with OCF/NI ratios swinging from -3.21 in 2024Q3 to 1.16 in 2025Q4, reflecting milestone revenue that generates accounting gains without immediate cash realization; as AC Immune's quarterly filings show, the gap between reported earnings and operating cash flow remains unpredictable.
The most telling divergence is 2024Q3, where reported net income of +$5.5M coincided with -$14.1M in operating cash flow — a $19.6M gap that suggests milestone revenue recognized on paper had not yet been collected. Conversely, loss-making quarters like 2025Q4 showed OCF (-$16.4M) closely tracking net income (-$14.4M), indicating that when no milestone is recognized, the accrual-to-cash gap narrows to near zero. This pattern implies the earnings quality issue is not systemic accrual manipulation but rather an inherent feature of milestone-driven economics, which investors should monitor as pipeline inflection points approach.
Persistent FCF Burn Offset by Episodic Infusions
Free cash flow has been persistently negative across eight of ten quarters, averaging roughly -$16M per quarter in loss periods, with FCF margins ranging from -12.2% to -56.2%; per AC Immune's reported cash flow statements, the only positive FCF quarters stem from large working capital inflows rather than operations.
The two positive FCF quarters — 2024Q2 (+$73.0M) and 2024Q4 (+$5.8M) — are entirely attributable to milestone collections, not operational profitability, as gross margins are zero or negative at the operating level. Recent quarters (2025Q1 through 2025Q4) show FCF burn of -$16.0M to -$19.2M per period, establishing a structural burn rate of approximately $65-77M annually. This trajectory is sustainable only if milestone inflows recur at intervals shorter than the cash runway, a dependency that warrants close monitoring of partnership timelines and cash balance disclosures.
Milestone Timing Drives Cash Flow Swings
Working capital is the dominant driver of cash flow volatility, with swings from +$91.2M inflow in 2024Q2 to -$24.2M outflow in 2024Q3, reflecting lumpy milestone collection cycles; as reported in AC Immune's SEC filings, the $22.4M inflow in 2024Q4 similarly traces to a single large receipt.
The magnitude of working capital swings — from +$91.2M to -$24.2M in consecutive quarters — dwarfs all other cash flow line items, including operating expenses and capex. This pattern suggests AC Immune collects large upfront or milestone payments from pharmaceutical partners, then deploys that cash over subsequent quarters. The negative WC change of -$23.8M across 2025 suggests the company is drawing down receivables or prepayments without a commensurate new milestone receipt, implying a potential cash flow inflection that investors should track in upcoming quarters.
Negligible Capex Confirms Asset-Light Model
Capital expenditure is negligible, ranging from $37K to $373K per quarter, representing a fraction of a percent of revenue in most periods; based on AC Immune's reported figures, the near-absence of capex confirms an asset-light, outsourcing-dependent development model with minimal infrastructure reinvestment requirements.
D&A of approximately $500-650K per quarter suggests a modest fixed asset base whose annual depreciation of roughly $2.4M far exceeds capex, indicating the company is not reinvesting to replace depreciating assets. This is consistent with a pre-commercial biotech that outsources manufacturing and clinical operations rather than maintaining proprietary facilities. The low capital intensity is a structural advantage for cash preservation, but it also means AC Immune has no manufacturing infrastructure to leverage if pipeline candidates reach commercialization — an operational consideration that would require significant capital deployment.
Cash Flow Opacity in Recent Quarters
Stock-based compensation is inconsistently reported, with zero in several quarters and $2.6M in 2026Q2, making it difficult to assess its cash-equivalent drag; additionally, operating cash flow is reported as $0 in 2026Q1 and 2026Q2, which may indicate data unavailability rather than actual neutral cash generation.
The $0 operating cash flow readings in 2026Q1 and 2026Q2 are analytically ambiguous — they could represent genuinely neutral cash generation coinciding with a positive $1.9M net income in 2026Q2, or they could reflect incomplete data. Without clarification, it is impossible to determine whether the company has achieved operational cash breakeven or if the milestone-driven burn has simply paused. The inconsistent SBC reporting also complicates a full cash-adjusted earnings assessment, as SBC of $2.6M in 2026Q2 would reduce cash-adjusted earnings to -$0.7M if treated as a real economic cost.