When I see a stock that has had a bad day, the first thing I look for in way of an explanation - when there is no 'news' - is the trading volume.
On 2-28-11 PNNT traded 1,328,835 shares when the average daily volume of trading for the last three months is 494,338 shares [Yahoo stats].
As a rule of thumb, if volume is over 30% higher than normal [and the rest of the stocks in that sector are having normal volume compared to the 3 month average], then there is more volatility than normal in the stock.
On 2-28-11, the volume was 2.69 times the normal volume. For PNNT to have that size of an increase in volume and only fall 15 cents [1.17%] is an indication that:
[1 - and not as likely given this is a one day event] PNNT is held by 'strong hands' - or a group of mostly committed long term holders of the stock.
- or -
[2 - and more probable given this is a one day event] There are a lot of potential PNNT buyers who are actively looking for a good entry point.
Could PNNT have several days of above average selling in a row? Yes. I have no certainty what might happen tomorrow. But if trading volume is 'average' for the next few days, then I would expect that PNNT will be up more than average [or down less than average] when compared to the rest of the sector.
There is a lot of noise out there that for a BDC to sell above its NAV is a bad thing. I have made the numeric case that such talk is - at least partially - BS.
It is only bad for a BDC to sell above its NAV if:  Its NAV is falling - and that is not the case for PNNT  Its NII/share is falling - and that is not the case for PNNT or  Its dividend is falling and its div/share is more than its NII/share - which is not the case for PNNT.