I agree with your observation that there seems no good reason for a share offering at this time.
But unfortunately the recent price manipulation is looking far too much for comfort like a repeat of the massive destruction of shareholder value the Insmed Board made possible last July.
We know that the net Short position increased by 350,000 on Wednesday's news.
7.8 million shares were traded on Wednesday. For all we know the net increase could have been the result of 4 million shares sold Short - with 3.65 million of those being sold to investors already Short who covered.
That would still have left an additional 3.8 million shares comprised of normal selling, normal buying and day traders who just profited from the drop and recovery (ending the day with unchanged positions).
There are only so many dumb retail investors out there who could have been conned into selling by the charade.
I hardly think it likely that many professional investors would simply gamble that the FDA will dismiss a statistically significant clinical benefit because the numbers for the primary outcome, though good, were less than statistically significant.
What reasonable expectation could a professional investor have had who sold thousands of shares, that other investors would in due course sell those shares back to him in at an even lower price?
I did indeed miss that bit - having missed the first 15 minutes or so because I'd forgotten it was happening until I saw a reminder here.
That is welcome news - though I'll feel happier when I've satisfied myself as to his choice of words.
In my experience these guys very rarely put themselves in a position which limits their options, unless doing so is unavoidable.
If, for example, FDA confirmation of Breakthrough Therapy status sends the share price straight over $100 I imagine the BOD would want to be able to strike while the iron is hot. Because they have enough capital to launch Arikace in Europe doesn't mean they won't need capital beyond that point.
As for today's trading the share price was held down in a range after a lunchtime move up. The trading pattern usually includes an assault right after the lunch hour in New York (1:00 EST), which leads me to believe its a hedge fund or big bank buying for a customer. It included big spikes throughout the day with small trades punctuated with big blocks five or six times. This can also be the market maker buying for customers. The short numbers today are also pretty low but, unlike the past two days, were a much bigger percentage of overall trades (43% today vs. 20% on average on Monday & Tuesday).
I looked at the short sales for both Monday and Tuesday - very few shares shorted. More likely there was short covering going on, even though the share price dropped on pretty low volume. As you said, likely day traders were working early in the week and someone who wanted the SP lower for there own reasons.