Steve Cohen just disclosed a 2.8 million share stake in a tiny pharmaceutical company that jumped 432% on Tuesday

In a filing out Tuesday after the market close, hedge fund manager Steve Cohen revealed an 8.3% ownership stake in tiny pharmaceutical company Celator Pharmaceuticals.

You might recognise the name: Celator shares jumped 432% in trading Tuesday after announcing a successful test of its new drug targeting a form of leukemia.

Through his family-office fund Point72 Asset Management, Cohen acquired just over 2.8 million shares some time over the past 10 days.

This position stood as of Monday’s close.

Tuesday’s disclosure came in a 13G filing, required whenever an investor takes a stake in a company equal to more than 5% of a company. Investors have a 10 day period from the time of purchase to disclose this position.

Based on Tuesday’s trading, Cohen’s stake increased in value by about $20.7 million from Monday to Tuesday’s close. Tuesday’s filing doesn’t say what Cohen’s cost-basis for the stake is.

Shares of Celator has been trading between about $1.50 and $2.10 per share over the last few weeks.

So while this isn’t a huge part of Cohen’s portfolio — Point72 has around $11 billion in assets — it’s not bad for a days work.

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