Deep Fission (FISN) Stock: Why It's Down Today
Updated Oct 20, 2026, 12:04 PM ET · intraday price
- Trading at $3.21 as of 12:04 PM ET, -12.30% vs the prior close of $3.66.
- Volume 892.42K shares, 2.6x its 50-day average (heavy).
- No new SEC filings since the prior session.
- No new insider buys or sales reported since the prior session.
FISN slides 12.3% to $3.21, a 3-month low on 2.6x normal volume. Trading at $3.21 (intraday, 12:04 PM ET), -12.30% vs the prior close of $3.66. Day range $3.08–$4.13, opened at $3.62.
FISN daily analysis — what happened
A plain-English, data-only note for every US trading day (today's note updates every 2 hours while the market is open). Newest first; older days stay archived below.
Oct 20, 2026 — FISN slides 12.3% to $3.21, a 3-month low on 2.6x normal volume
- Trading at $3.21 (intraday, 12:04 PM ET), -12.30% vs the prior close of $3.66. Day range $3.08–$4.13, opened at $3.62.
- Volume was 892.42K shares, 2.6x its 50-day average of 341.95K — unusually heavy trading.
- Price is -50.3% vs its 50-day average ($6.45).
- 52-week range $3.08–$19.00; the current price sits at 1% of that range, 83.1% below the 52-week high.
Oct 19, 2026 — FISN jumps 6.1% to $3.66 on 2.2x normal volume
- Closed at $3.66, +6.09% vs the prior close of $3.45. Day range $3.39–$3.81, opened at $3.59.
- Volume was 714.67K shares, 2.2x its 50-day average of 331.27K — unusually heavy trading.
- Price is -44.1% vs its 50-day average ($6.55).
- 52-week range $3.39–$19.00; today's close sits at 2% of that range, 80.7% below the 52-week high.
Oct 16, 2026 — FISN slides 5.5% to $3.45, a 3-month low, 8 down days in a row
- Closed at $3.45, -5.48% vs the prior close of $3.65. Day range $3.40–$3.75, opened at $3.66.
- Volume was 362.90K shares, 1.1x its 50-day average of 329.05K.
- Price is -48.2% vs its 50-day average ($6.66).
- 52-week range $3.40–$19.00; today's close sits at 0% of that range, 81.8% below the 52-week high.
- That makes 8 straight losses.
Oct 15, 2026 — FISN slides 5.2% to $3.65, a 3-month low on 2.1x normal volume
- Closed at $3.65, -5.19% vs the prior close of $3.85. Day range $3.55–$3.85, opened at $3.84.
- Volume was 690.10K shares, 2.1x its 50-day average of 323.75K — unusually heavy trading.
- Price is -46.1% vs its 50-day average ($6.77).
- 52-week range $3.55–$19.00; today's close sits at 1% of that range, 80.8% below the 52-week high.
- That makes 7 straight losses.
Oct 14, 2026 — FISN slides 4.0% to $3.85, a 3-month low, 6 down days in a row
- Closed at $3.85, -3.99% vs the prior close of $4.01. Day range $3.63–$3.98, opened at $3.95.
- Volume was 490.50K shares, 1.5x its 50-day average of 319.85K.
- Price is -44.0% vs its 50-day average ($6.87).
- 52-week range $3.63–$19.00; today's close sits at 1% of that range, 79.7% below the 52-week high.
- That makes 6 straight losses.
Oct 13, 2026 — FISN slides 4.1% to $4.01, a 3-month low, 5 down days in a row
- Closed at $4.01, -4.07% vs the prior close of $4.18. Day range $3.96–$4.20, opened at $4.02.
- Volume was 417.30K shares, 1.3x its 50-day average of 315.48K.
- Price is -42.5% vs its 50-day average ($6.98).
- 52-week range $3.96–$19.00; today's close sits at 0% of that range, 78.9% below the 52-week high.
- That makes 5 straight losses.
Oct 12, 2026 — FISN slides 6.1% to $4.18, a 3-month low, 4 down days in a row
- Closed at $4.18, -6.07% vs the prior close of $4.45. Day range $4.12–$4.56, opened at $4.50.
- Volume was 417.10K shares, 1.4x its 50-day average of 308.22K.
- Price is -41.1% vs its 50-day average ($7.10).
- 52-week range $4.12–$19.00; today's close sits at 0% of that range, 78.0% below the 52-week high.
- That makes 4 straight losses.
Oct 9, 2026 — FISN slides 4.5% to $4.45, a 3-month low, 3 down days in a row
- Closed at $4.45, -4.51% vs the prior close of $4.66. Day range $4.40–$4.77, opened at $4.70.
- Volume was 416.50K shares, 1.4x its 50-day average of 301.56K.
- Price is -38.2% vs its 50-day average ($7.20).
- 52-week range $4.40–$19.00; today's close sits at 0% of that range, 76.6% below the 52-week high.
- That makes 3 straight losses.
Oct 8, 2026 — FISN slides 8.3% to $4.66, a 3-month low
- Closed at $4.66, -8.27% vs the prior close of $5.08. Day range $4.61–$5.08, opened at $5.05.
- Volume was 477.20K shares, 1.6x its 50-day average of 294.47K.
- Price is -36.2% vs its 50-day average ($7.30).
- 52-week range $4.61–$19.00; today's close sits at 0% of that range, 75.5% below the 52-week high.
Oct 7, 2026 — FISN slides 7.1% to $5.08, a 3-month low
- Closed at $5.08, -7.13% vs the prior close of $5.47. Day range $5.06–$5.46, opened at $5.40.
- Volume was 194.90K shares, 0.7x its 50-day average of 296.96K.
- Price is -31.4% vs its 50-day average ($7.41).
- 52-week range $4.90–$19.00; today's close sits at 1% of that range, 73.3% below the 52-week high.
Oct 6, 2026 — FISN rises 1.7% to $5.47
- Closed at $5.47, +1.67% vs the prior close of $5.38. Day range $5.40–$5.85, opened at $5.40.
- Volume was 277.70K shares, 0.9x its 50-day average of 295.20K.
- Price is -27.1% vs its 50-day average ($7.50).
- 52-week range $4.90–$19.00; today's close sits at 4% of that range, 71.2% below the 52-week high.
Oct 5, 2026 — FISN slides 3.4% to $5.38
- Closed at $5.38, -3.41% vs the prior close of $5.57. Day range $5.31–$5.73, opened at $5.60.
- Volume was 197.00K shares, 0.7x its 50-day average of 292.66K.
- Price is -29.1% vs its 50-day average ($7.59).
- 52-week range $4.90–$19.00; today's close sits at 3% of that range, 71.7% below the 52-week high.
Oct 2, 2026 — FISN jumps 7.5% to $5.57 on 1.8x normal volume
- Closed at $5.57, +7.53% vs the prior close of $5.18. Day range $5.25–$6.05, opened at $5.44.
- Volume was 520.70K shares, 1.8x its 50-day average of 284.91K — unusually heavy trading.
- Price is -27.5% vs its 50-day average ($7.69).
- 52-week range $4.90–$19.00; today's close sits at 5% of that range, 70.7% below the 52-week high.
FISN bull case vs bear case (from the data)
- No clear positive signal in the price trend, filings or insider data right now.
- Price is -50.3% vs its 50-day average — short-term trend is down.
- Latest fiscal-year net income: loss of $61.00M.
- Share count up 1078.1% in a year (dilution).
- High volatility: average daily move of 6.0% over 20 sessions.
- Thin trading (under $2M a day on average) can mean wide bid/ask spreads.
FISN latest news & SEC filings
Every SEC filing by or about FISN in the last 120 days, explained in plain English. Updated daily, with a same-day refresh for new filings.
Sep 21, 2026 · Form 8-K — Major event / current report
Current report — a filing companies must make within 4 business days of a major event
- Item 7.01 — Released information under Regulation FD (e.g. a presentation or press release).
Aug 3, 2026 · Form 10-Q — Quarterly report
Quarterly report (unaudited financial statements for the quarter)
Quarter ended Jun 30, 2026:
- Net income: -$31.01M (prior year -$3.80M) (loss widened vs Jun 30, 2025)
- Diluted EPS: -$0.56 (prior year -$0.27) (loss widened vs Jun 30, 2025)
Jul 29, 2026 · Form 8-K — Major event / current report
Current report — a filing companies must make within 4 business days of a major event
- Item 8.01 — Reported other events the company considers important.
Jul 27, 2026 · Form 4 — Insider trade
Insider trade report (Form 4) — a director, officer or 10%+ owner changed their holdings
Insider holdings update with no common-stock transactions in the table (often options or derivative awards only).
Jul 27, 2026 · Form 4 — Insider trade
Insider trade report (Form 4) — a director, officer or 10%+ owner changed their holdings
Insider holdings update with no common-stock transactions in the table (often options or derivative awards only).
Jul 27, 2026 · Form 4 — Insider trade
Insider trade report (Form 4) — a director, officer or 10%+ owner changed their holdings
Insider holdings update with no common-stock transactions in the table (often options or derivative awards only).
Jul 27, 2026 · Form 4 — Insider trade
Insider trade report (Form 4) — a director, officer or 10%+ owner changed their holdings
Insider holdings update with no common-stock transactions in the table (often options or derivative awards only).
Jul 20, 2026 · Form S-8 — Employee share plan registration
Registration of shares for employee stock plans (S-8)
Jul 17, 2026 · Form 8-K — Major event / current report
Current report — a filing companies must make within 4 business days of a major event
- Item 5.02 — Change in directors or officers (appointment, departure or pay).
- Item 5.07 — Reported shareholder vote results.
Jun 22, 2026 · Form 8-K — Major event / current report
Current report — a filing companies must make within 4 business days of a major event
- Item 8.01 — Reported other events the company considers important.
Things to know before you trade FISN
- How much it moves: over the last 20 sessions the average daily move was 6.01% (largest 13.3%). That is a volatile stock.
- Liquidity: about 465.39K shares (≈$1.49M) trade per day on average. Thin volume can mean wider bid/ask spreads.
- 52-week position: $3.21 vs a range of $3.08–$19.00 (1% of the range).
- Dividends: no cash dividends in the last 2 years.
- Splits: none in the last 2 years.
- Insider trades (Form 4, last 12 months, recent 25 shown): 0 open-market buys, 0 sales.
- Latest filings: 8-K Sep 21, 2026; 10-Q Aug 3, 2026; 8-K Jul 29, 2026.
- Share count: 58.91M shares outstanding (Jul 27, 2026), +1078.1% vs a year earlier — notable dilution.
- Listing: Nasdaq · industry: Electric Services.
FISN market data (last 20 sessions)
| Date | Open | High | Low | Close | Volume |
|---|---|---|---|---|---|
| Oct 20, 2026 | 3.62 | 4.13 | 3.08 | 3.21 | 892.42K |
| Oct 19, 2026 | 3.59 | 3.81 | 3.39 | 3.66 | 715.00K |
| Oct 16, 2026 | 3.66 | 3.75 | 3.40 | 3.45 | 362.90K |
| Oct 15, 2026 | 3.84 | 3.85 | 3.55 | 3.65 | 690.10K |
| Oct 14, 2026 | 3.95 | 3.98 | 3.63 | 3.85 | 490.50K |
| Oct 13, 2026 | 4.02 | 4.20 | 3.96 | 4.01 | 417.30K |
| Oct 12, 2026 | 4.50 | 4.56 | 4.12 | 4.18 | 417.10K |
| Oct 9, 2026 | 4.70 | 4.77 | 4.40 | 4.45 | 416.50K |
| Oct 8, 2026 | 5.05 | 5.08 | 4.61 | 4.66 | 477.20K |
| Oct 7, 2026 | 5.40 | 5.46 | 5.06 | 5.08 | 194.90K |
| Oct 6, 2026 | 5.40 | 5.85 | 5.40 | 5.47 | 277.70K |
| Oct 5, 2026 | 5.60 | 5.73 | 5.31 | 5.38 | 197.00K |
| Oct 2, 2026 | 5.44 | 6.05 | 5.25 | 5.57 | 520.70K |
| Oct 1, 2026 | 5.15 | 5.24 | 4.90 | 5.18 | 336.50K |
| Sep 30, 2026 | 5.29 | 5.47 | 5.05 | 5.13 | 281.90K |
| Sep 29, 2026 | 5.64 | 5.75 | 5.20 | 5.25 | 436.60K |
| Sep 28, 2026 | 6.30 | 6.44 | 5.40 | 5.42 | 579.10K |
| Sep 25, 2026 | 6.64 | 6.75 | 6.23 | 6.25 | 578.00K |
| Sep 24, 2026 | 7.77 | 7.87 | 6.84 | 6.95 | 710.10K |
| Sep 23, 2026 | 8.15 | 8.21 | 7.62 | 7.80 | 316.30K |
About Deep Fission
Deep Fission (FISN) is listed on the Nasdaq and classified by the SEC under “Electric Services”. Its business address is in BERKELEY, CA. State of incorporation: DE. Fiscal year ends December 31. SEC CIK 1918102.
FISN board of directors & executives
From SEC Form 3/4/5 insider filings made in the last 12 months (date = latest filing).
Directors
| Name | Role | Latest filing |
|---|---|---|
| Jonathon Angell | Director | Jul 27, 2026 |
| Thomas S Glanville | Director | Jul 27, 2026 |
| Tepper Leslie Goldman | Director | Jul 27, 2026 |
| Blake Janover | Director | Jul 27, 2026 |
Executive officers
| Name | Title | Latest filing |
|---|---|---|
| Michael Allen Brasel | Chief Operating Officer | Mar 10, 2026 |
| Jonathan H Gordon | General Counsel | Mar 10, 2026 |
| Elizabeth Muller | Chief Executive Officer | Mar 10, 2026 |
| Richard Muller | Chief Technology Officer | Mar 10, 2026 |
| Mark Wayne Peres | Chief Nuclear Officer | Mar 10, 2026 |
| William Mark Schmitz | Chief Financial Officer | Mar 10, 2026 |
Recent insider buys & sales
| Date | Insider | Type | Shares | Price |
|---|---|---|---|---|
| No open-market insider buys or sales reported in the last 12 months. | ||||
FISN financials (annual, from XBRL filings)
| Fiscal year end | Revenue | Net income | Diluted EPS | Operating cash flow |
|---|---|---|---|---|
| Dec 31, 2025 | — | $-61.00M | — | $-13.05M |
| Dec 31, 2024 | — | $-5.71M | -0.57 | $-2.80M |
| Dec 31, 2023 | — | $-47.62K | -0.01 | $-46.28K |
| Dec 31, 2022 | — | $-49.41K | -0.01 | $-40.06K |
Latest balance sheet: total assets $107.31M, total liabilities $8.55M, cash $93.02M (as of Jun 30, 2026).
FISN earnings / results-day log
| Date | Filing | Close that day |
|---|---|---|
| No 8-K earnings releases in recent filings. | ||
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Information only, not investment advice. BuyMeWhiskey is not a registered investment adviser or broker-dealer; nothing here is a recommendation to buy, sell or hold any security, and there are no price targets. Data comes from SEC EDGAR filings and public end-of-day market data and may be delayed or contain errors. Verify with the company's filings before making decisions. Prices: intraday data as of Oct 20, 2026, 12:04 PM ET. Filings: SEC EDGAR. Refreshed every 2 hours during US market hours.