Less than a handful of those old shareholders have sold for a loss and moved on. The majority are bag holders. Sure some may have 'lowered their basis' by taking big risks in doubling down, but that doesn't suddenly - magically - lower your basis below the current price. Can't believe you think it does!
As for new investors - really? when, why and who? (be specific). Because over the past few years Amarin has only received one favorable upgrade. Who buys a fallen angel with negative fundamental metrics, falling revenue, and corporate chaos? If there are any new investors, they are short term traders, trading a TA counter-trend setup (like myself). The only long term holders are shorts holding the down trend, and underwater longs holding... hoping for a buyout.