Pioneer HPM-40 Vintage Speakers

In my day the holy grail of Pioneer speakers was the HPM-100 model which, I think, was the largest?  Frankly speaking you really don't see much of the "vintage" Pioneer/Sansui/Marantz receiver gear here, but eBay seems to have a large audience for that.  Best of luck!

The Audiogon BLUEBOOK for used equipment relates that a used pair of HPM 100 might fetch around $290 on average. Again, the BB average pertains to items listed and sold here, so methinks your target audience is eBay. I've bought a few receivers there with no issues. 

Pioneer made an HPM150 and an HPM200 also.  I'm old, I sold these at the very end of their retail life cycle.  
The 40's were a bit more balanced than the 100's, but both could get edgy.... I've never measured the 40's, but the 100's were about 90db sensitivity up to around 1k,  then rose 5 or 6 db above that,  the mids & highs were quite a bit hotter.... I never got the impression from the 40's that they were that far off.  
As far as selling,  if they look great, you'll sell them,  if you can find someone with a fond memory of these,  you'll get a decent price,  If not,  its another cheap speaker. They manufactured from 1976 to 1979.  I sold them in 79