Inside Darwin Global’s Monster INSM Trade – Trehan Strikes Again
Two trades in this little understood biotech have netted ~$42M+ in paper gains
On June 10 all eyes in the market were on Insmed Inc. (INSM).
The small-cap biotech surged over 30% intraday after the company released overwhelmingly positive Phase 2b results for its pulmonary arterial hypertension (PAH) treatment. For some, it was just another headline. But for one hedge fund — and one man — it was a multi-million-dollar payday.
Darwin Global Management is helmed by Dr. Abhishek Trehan, a British-born investor and Harvard MBA who quietly built one of the most successful – and low-profile – funds in Europe. On June 10, Dr. Trehan seemingly added a few million dollars to his growing fortune, on which seems to be rising at an almost exponential pace.
The INSM Payoff: From Smart Money to Big Money
According to 13F filings, Darwin Global Management added 2,437,437 shares of INSM in the Q2 window, likely beginning just before or around April 24, when the stock was trading in the $26–28 range. That position, now worth around $43 per share, ballooned in value.
Let’s break down the trade:
Shares purchased: 2.44 million
Estimated purchase price: ~$27
Current price: ~$43
Unrealized gain per share: $16
Total paper gain:
$39 million
That’s a $39 million profit — in under two months
And this is just the long equity position. The real payday may be from the options market, where a whale was spotted making a high-conviction trade on April 24.
The Call Option Mystery: $1 Million Turns Into $5 Million
On April 24, someone bought 5,000+ INSM June 20, 2025 $80 Calls got $2.80 each.
That’s $1.4 million in premium — an aggressive, high-risk trade.
At the time of the trade, INSM was trading in the $26–27 range. These calls are deep out-of-the-money calls and require the stock price to triple just to reach the strike.
Fast forward six weeks, and INSM explodes to $43 per share.
While that still falls short of the $80 strike, the calls still skyrocketed in value, trading over $10 peak intraday today due to the massive surge in momentum and Implied Volatility.
Let’s say our mystery trader exited at $10 per contract:
5,000 contracts × $10 × 100 = $5 million
Cost basis: 5,000 × $2.80 × 100 = $1.4 million
Net profit: $3.6 million
ROI: ~257% in six weeks
This isn’t some random prop trader buying a lottery ticket, but the kind of asymmetric trade only seasoned, connected, or ultra-confident capital makes.
So, who is behind it?
Enter Dr. Abhishek Trehan — And Possibly, His Cousin?
Dr. Abhishek Trehan, founder and CIO of Darwin Global Management, is a figure wrapped in intellect, precision, and ever increasing wealth. With degrees from Oxford and Harvard, Trehan launched Darwin in 2020. By 2025, Darwin Global was managing over $2.5 billion, with a clear preference for biotech stocks.
But here’s where things get interesting.
Regulatory disclosures show Darwin loaded up on INSM shares during Q2. Meanwhile, that massive call option bet occurred on April 24 — before the average investor would have had any inkling of the trial results that would later send the stock flying.
Could the call buyer have been someone connected to Darwin Global? A satellite fund? A former colleague? Or, in a scenario ripe for speculative curiosity, a family member?
Trehan is a British citizen, and records show he maintains close family ties in London and Birmingham, where several family entities are registered. Could one of these individuals — say, a financially savvy cousin or associate — have made the trade?
Certainly possible. While there’s no public evidence linking Trehan directly to the options purchase, the timing, scale, and alignment with Darwin’s equity position raise eyebrows. Hedge fund families often operate through a wide network of private vehicles, trusts, and offshore accounts.
And in high-stakes finance, a 6-week $1.4M to $5M flip doesn’t happen by chance. It’s executed with conviction and information.
The Trehan Playbook: Quiet Execution, Outsized Returns
Dr. Trehan is not a flashy investor. He doesn’t go on CNBC. He doesn’t tweet. He lets his performance speak for itself, and it speaks volumes.
Darwin has quietly outperformed larger hedge funds for three years straight.
He runs a concentrated strategy, often investing heavily in misunderstood biotech names — including Verona Pharma, Apellis — and now Insmed.
He’s known for deep diligence into clinical trial forecasting, often months ahead of broader Wall Street consensus, suggesting he is no stranger to well-placed information sources.
Insiders in the London financial scene say Trehan operates like a chess master — always five moves ahead, never revealing his hand.
Now, with INSM, it appears he made another checkmate move.
The Shadow Game of Smart Money
Let’s put this into context:
Wall Street thrives on pattern recognition. And INSM has all the patterns:
Unusual option activity
Quiet but heavy institutional accumulation
Surprise catalyst
Explosive re-pricing
Regardless of whether Dr. Trehan or someone in his circle bought the 5,000 call contracts, the puzzle piece fit together. It may never be confirmed — but it doesn’t need to be. In markets, actions speak louder than press releases.
And the market just shouted: Darwin wins again.
Final Thoughts
INSM’s run is far from over — especially with a potential M&A suitor now more likely than ever.
But as of today, one thing is certain:
Darwin Global made tens of millions
Abhishek Trehan’s legendary status in biotech investing continues to grow.
And someone — maybe connected, or even just very clever — turned $1 million into $5 million by betting on the right horse, at the right time.
That’s not luck. That’s what the Street calls informed conviction.