Biogen has been an active stock. Photo: John Tlumacki/The Boston Globe via Getty Images

A lot of Biogen's value hinges on whether federal scientists and regulators will approve or reject its drug candidate for Alzheimer's.

Driving the news: The drug, called aducanumab, has attracted people like Warren Buffett to invest in Biogen's stock on the assumption the drug will score approval for a patient population that desperately seeks a treatment. But other wealthy investors, like Ray Dalio, have taken a less sanguine view and dumped Biogen completely.

By the numbers: Warren Buffett's Berkshire Hathaway hadn't owned any shares of Biogen until it bought 648,000 new shares in the last quarter of 2019, according to regulatory documents flagged by Meg Tirrell of CNBC.

Yes, but: Ray Dalio of Bridgewater Associates sold off all of its 237,000 Biogen shares, according to regulatory filings.

  • Parnassus Investments and HealthCor Management likewise divested all of their Biogen stakes, while a handful of others significantly dialed back investments.

The big picture: The FDA is expected to review and rule on Biogen's application at some point this year. The recent stock trading around Biogen gives a glimpse at how much is riding on this drug, and how much uncertainty there is around approval.

Go deeper: Why there's skepticism around Biogen's Alzheimer's drug

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May 27, 2020 - Health

Fauci: Data is "really quite evident" against hydroxychloroquine for coronavirus

Anthony Fauci told CNN Wednesday that the scientific data "is really quite evident now about the lack of efficacy" of hydroxychloroquine as a coronavirus treatment.

Driving the news: The comments came in response to news that France on Wednesday banned the use of hydroxychloroquine to treat the virus, after a large retrospective study in The Lancet found an increased risk of heart problems and death among coronavirus patients who took the anti-malarial drug.

May 26, 2020 - Health

The final data for remdesivir is in

Gilead is ramping up production of remdesivir. Photo: Josh Edelson/AFP via Getty Images

Remdesivir, officially branded as Veklury, does indeed work for patients hospitalized with COVID-19, according to expert reads of the data that were published in the New England Journal of Medicine.

Yes, but: The benefits remain rather limited, as patients on the drug leave the hospital in 11 days vs. 15 days.

Professional investors may be dipping their toes back into stocks

Illustration: Aïda Amer/Axios

The historic inflow to money market funds from institutional asset managers finally paused last week and that could mean investors are starting to believe in equities again after steering clear of making major investments over the last two months.

What happened: Money market funds, which are effectively savings accounts, saw just $1.41 billion of inflows for the week ending May 21, data from the Investment Company Institute showed — and it was entirely from retail investors.