Sarissa Capital Management LP's 13F Portfolio ($177.9M, Q2 2026)

Sarissa Capital Management LP's disclosed holdings carry a Herfindahl concentration index of 0.166 — mathematically equivalent to about 6 equally-sized positions, close to its 10 actual disclosed holdings. Value is spread relatively evenly across the portfolio rather than concentrated in a handful of names.

Position sizes are fairly uniform across the portfolio (a coefficient of variation of 0.85), suggesting a disciplined, rules-based approach to how much capital goes into each idea.

Recent activity leans toward adding more aggressively to already-large existing positions than to newly initiated ones (a 2.9 percentage-point tilt) — a pattern consistent with a momentum-following approach.

Sector classification currently covers about 34% of this portfolio's disclosed value; the remainder includes holdings (e.g. unmapped tickers, options, or other security types) not yet covered by our sector mapping.