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QSI
Quantum-Si Incorporated Class A Common Stock
stock NASDAQ

At Close

Sep 29, 2026 3:59:48 PM EDT

0.9600USD+20.792%(+0.1650)22,869,241

0.9100Bid 1.00Ask 0.0900Spread

Pre-market

Sep 29, 2026 9:17:30 AM EDT

0.8154USD+2.566%(+0.0204)4,184

After-hours

Sep 29, 2026 4:59:30 PM EDT

0.9556USD-0.489%(-0.0047)64,631

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QSI Reddit Mentions

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QSI Specific Mentions

As of Sep 30, 2026 12:09:33 AM EDT (<1 min. ago)

Includes all comments and posts. Mentions per user per ticker capped at one per hour.

8 hr ago • u/saasfin • r/stockstobuytoday • sideways_chop_all_day_did_anyone_actually_trade • Stocks • B

A lot of back-and-forth action today without much conviction from buyers or sellers.
### 🧭 Where we closed:
* **SPY:** $764.13 (🔴 -0.1933%)
* **QQQ:** $737.56 (🟢 +0.1398%)
* **VIX:** $16.77 (✅ Cooling)
---
### 🔥 The Movers:
**🚀 Top Gainers:**
* **SDEV** | $3.25 (106.99%)
* **IOVA** | $14.69 (33.71%)
* **NAUT** | $1.38 (24.07%)
**📉 Top Losers:**
* **ACHR** | $5.04 (-3.08%)
* **PSKY** | $9.95 (-3.16%)
* **RKLB** | $69.61 (-3.57%)
**🌊 Volume Leaders:**
* **IOVA** | $14.69 (33.71%)
* **CCL** | $25.15 (13.57%)
* **QSI** | $0.96 (20.75%)
---
💬 **What was your best (or worst) trade of the day?**
---
📖 *Trying to figure out next day's play? Use free AI powered institutional flow, max pain levels, and breakout scanners for the after-hours session. [Check the live data here](https://stockbuyvest.com/screener).*

13 hr ago • u/Other-Silver1672 • r/pennystocks • the_lounge • C

16 hr ago • u/SPAC_Time • r/Spacstocks • quantumsi_presents_interim_proteus_data_at_world • Post Merger • T

Quantum-Si Presents Interim Proteus™ Data at World HUPO 2026 Demonstrating a Significant Step Change in Performance Compared to Platinum® Pro - QSI

8 hr ago • u/saasfin • r/stockstobuytoday • sideways_chop_all_day_did_anyone_actually_trade • Stocks • B

A lot of back-and-forth action today without much conviction from buyers or sellers.
### 🧭 Where we closed:
* **SPY:** $764.13 (🔴 -0.1933%)
* **QQQ:** $737.56 (🟢 +0.1398%)
* **VIX:** $16.77 (✅ Cooling)
---
### 🔥 The Movers:
**🚀 Top Gainers:**
* **SDEV** | $3.25 (106.99%)
* **IOVA** | $14.69 (33.71%)
* **NAUT** | $1.38 (24.07%)
**📉 Top Losers:**
* **ACHR** | $5.04 (-3.08%)
* **PSKY** | $9.95 (-3.16%)
* **RKLB** | $69.61 (-3.57%)
**🌊 Volume Leaders:**
* **IOVA** | $14.69 (33.71%)
* **CCL** | $25.15 (13.57%)
* **QSI** | $0.96 (20.75%)
---
💬 **What was your best (or worst) trade of the day?**
---
📖 *Trying to figure out next day's play? Use free AI powered institutional flow, max pain levels, and breakout scanners for the after-hours session. [Check the live data here](https://stockbuyvest.com/screener).*

13 hr ago • u/Other-Silver1672 • r/pennystocks • the_lounge • C

16 hr ago • u/SPAC_Time • r/Spacstocks • quantumsi_presents_interim_proteus_data_at_world • Post Merger • T

Quantum-Si Presents Interim Proteus™ Data at World HUPO 2026 Demonstrating a Significant Step Change in Performance Compared to Platinum® Pro - QSI

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