Exited position

Carl Icahn’s Biogen Inc (BIIB) position

Reported position history, portfolio importance and verified filing changes from public SEC disclosures.

Icahn EnterprisesVerified through Q2 2026
Relationship snapshot

At a glance

The full verified relationship, including prior ownership episodes and exits where supported.

First reportedQ4 2007Earliest verified positive filing snapshot
Latest statusExited positionBased on the latest supported relationship state
Peak shares3.50MHighest verified quarter-end share count
Quarters reported14Verified quarters with shares above zero
What happened?

Icahn Enterprises first reported Biogen Inc in Q4 2007. The reported position was increased and reduced across later filings. The latest verified relationship event shows that Icahn Enterprises sold the entire position in Q2 2011, and the stock is no longer reported in the latest verified portfolio.

Verified SEC history

Position over time

See the same verified relationship through reported shares, portfolio weight or reported value.

Metric

Gaps indicate periods that cannot be safely connected or where a verified corporate action changes the raw share scale. Stock price, when available, is market context and not a transaction price.

Key filing events

What changed

Latest filing plus the most meaningful reported changes. Unchanged quarters are collapsed by default.

Q2 2011
Sold the entire position−3.22M shares · No shares reported at quarter-end
Q4 2008
Sold 8.2% of the position−287.21K shares · 3.22M shares remained
Filing context

Quarter-end price $47.63 · Estimated holding basis $55.57

Q3 2008
Bought 40.8% more+1.02M shares · 3.50M shares reported after the change
Filing context

Quarter-end price $50.29 · Estimated holding basis $55.57

Q1 2008
New position+2.49M shares · 2.49M shares reported
Filing context

Quarter-end price $61.69 · Estimated holding basis $57.73

10 unchanged quarters are collapsed by default.

Portfolio importance

How important was Biogen Inc in Icahn Enterprises’s reported portfolio?

Relative importance is measured only within the verified primary non-option reported portfolio for each quarter.

Last reported portfolio weight3.5%Q1 2011
Last reported rank#5of 20 reported positions
Peak portfolio weight6.1%Q1 2009
Best historical rank#3Q4 2009
At peak importanceQ1 2009
BIIB
6.1%
Largest holding
64.6%
Cross-investor discovery

Who else owns Biogen Inc?

Also reported by 1 other tracked investor in their latest verified filings.

Joel GreenblattGotham Asset Management
BIIB0.1% of reported portfolio
Explore Biogen Inc across all tracked investors →
SEC evidence & methodology

SEC filing evidence

Market context and filing-derived values are kept separate from actual transaction prices, which 13F filings do not disclose.

Latest verified stock price$216.012026-09-16

Market context only; not an investor transaction price.

Latest verified investor filingQ2 2026 · filed 2026-08-14
Open SEC filing ↗

This tracker follows Carl C. Icahn’s consolidated reporting group’s Form 13F disclosures—not Carl Icahn’s personal brokerage account. Form 13F reports quarter-end U.S.-listed positions and certain options, but it does not reveal exact trade dates, execution prices, short positions or the purpose of an option position.