Recap
Hey guys! If you’re new here, I am running a 6 month long experiment to see if a Large Language Model (like ChatGPT) can be a skilled micro-cap portfolio manager. I give it daily closing data at the end of every trading day and it has full control over its assets. Also, once every week it gets to use Deep Research to completely reevaluate it’s account. Can ChatGPT carve consistent alpha in the dangerous world of micro-cap stocks? Lets find out.
Overview
The portfolio experienced little change, however the two stocks themselves moved very differently. SLS had a run up of over 14% over the past week, while MIST was down 26%.
With the final week upcoming, ChatGPT has tried to distance its strategy from binary catalyst to a what it describes as a “balanced, risk controlled setup”. The main changes this week include SLS shares by eight shares and buying 20 shares in new position JSPR.
Performance Graph
Metrics
[ Risk & Return ]
Max Drawdown: -50.33% on 2025-11-06
Sharpe Ratio (period): -0.4263
Sharpe Ratio (annualized): -0.2380
Sortino Ratio (period): -0.4974
Sortino Ratio (annualized): -0.2777
[ CAPM vs Benchmarks ]
Beta (daily) vs ^GSPC: 1.1340
Alpha (annualized) vs ^GSPC: -32.66%
R² (fit quality): 0.027 Obs: 120
Note: Short sample and/or low R² — alpha/beta may be unstable.
[ Snapshot ]
Latest ChatGPT Equity: $ 83.23
$100.0 in S&P 500 (same window): $ 110.15
Cash Balance: $ 22.45
Current Portfolio
ticker shares buy price cost basis stop loss PnL
MIST 14.0 1.75 24.50 1.6 +5.60
SLS 13.0 1.41 18.33 1.1 +12.35
Portfolio Review
To see the full report: Click Here
Condensed Thesis Review Summary
As the portfolio enters the final week of the 6-month experiment, positioning has shifted from aggressive, single-catalyst bets toward a more balanced, risk-managed setup. The goal for Week 26 is to preserve gains, limit downside, and retain upside optionality.
Milestone Pharmaceuticals (MIST)
- Status: High-conviction thesis successfully validated with FDA approval of Cardamyst on Dec 12, 2025.
- Current View: Transitioning from a regulatory catalyst to a commercialization and growth story.
- Why We Hold:
- First-in-class, self-administered PSVT therapy
- Regulatory and manufacturing risks resolved
- Strong balance sheet with ~$82M cash plus a $75M milestone payment
- Meaningful re-rating potential from current ~$2.15 price
- Action: Holding 14 shares with a tightened $1.80 stop.
- Role in Portfolio: De-risked anchor position providing stability with upside.
SELLAS Life Sciences (SLS)
- Status: Highly binary “moonshot” ahead of imminent Phase 3 REGAL trial results.
- Upside Case:
- Promising Phase 2 survival data
- Large unmet need in AML CR2
- Trial duration suggests possible efficacy
- Cash runway into 2027 limits downside in failure
- Risk Management:
- Trimmed ~62% of position, leaving 5 shares at near-zero cost basis
- Exposure is now limited to “house money”
- Outcomes:
- Positive result could lead to a sharp revaluation
- Negative result would be painful but manageable
- Role in Portfolio: Asymmetric upside optionality without existential risk.
Jasper Therapeutics (JSPR)
- Status: New position aimed at exploiting a valuation disconnect rather than a binary event.
- Why We Bought:
- Market cap roughly equal to cash on hand (~$50M)
- Positive early asthma data following prior trial disappointment
- Signs of improving momentum and sentiment
- Risk Control:
- ~20 shares purchased around $1.90
- Stop-loss at $1.50
- Goal: Capture a short-term rebound or early leg of a broader recovery.
- Role in Portfolio: Tactical, non-binary alpha source to diversify risk.
Overall Portfolio Thesis (Week 26)
- The portfolio now reflects a “balance offense and defense” mindset:
- MIST anchors gains and reduces volatility
- SLS preserves exposure to a transformative upside event
- JSPR adds a valuation-driven rebound opportunity
- Compared to earlier weeks’ all-or-nothing biotech bets, risk is now spread across multiple potential paths to success.
- Position sizing and stops ensure that even adverse outcomes won’t derail overall performance.
Final Outlook
- Best Case: SLS succeeds, JSPR rebounds, MIST grinds higher → strong chance to narrow or beat the benchmark.
- Worst Case: One or two theses fail, but downside remains cushioned.
- Bottom Line: The portfolio is positioned boldly but prudently, maximizing asymmetry while respecting risk into the final week.
External Links
To see all past deep research reports and summaries: Here
Full chats: Here
Have a question? Check out: Q&A
If you’d like to see the raw logs and full portfolio simulation code: GitHub Page
My X account: NathanS729
If you have any suggestions or advice, my Gmail is: [email protected]
Disclaimer
This project is purely educational and research-focused. Nothing here should be taken as financial advice. Full disclaimer: Here