This is a cylical industry that is still going down on earnings. The P/E doesn't really mean anything right now just as it doesn't for competitors that are reporting losses. In a market like this the most telling valuation is Price to Book. The tangible book for PJC is around $38 to $39 a share and it should trade in the context of 0.7x to 0.9x which explains the $27 to $36 trading range that it is currently stuck within.
Piper is very levered to corporate finance (M&A and IPO markets) in select sectors (Healthcare, Consumer, Tech, Finance in that order) and municipal finance. The muni market is holding in well and the company is taking market share. However, the weakness in coporate finance is more than offsetting any strength in munis. The only deals the firm is doing right now are in Europe, in Solar, or in China. In a good market PJC can trade at a premium to tangible book but there isn't a reason to own the stock at $35 or $36 a share in a market like this.