Approached by a publishing company, no money upfront, but will want 50% of subscription fees. Fishy?

I produce an investing podcast that surrounds new prediction technology. We have bi/tri weekly discussions on the market and particular stock picks that seem promising based on this tech. My partner was approached by a marketing/publishing firm suggesting that they ghostwrite a book (for free) and they would schedule for one of us to appear on select podcasts within their network (they claim one of them has 9 million listeners). I don't really know what to ask but to me this doesn't seem...

Approached by a publishing company, no money upfront, but will want 50% of subscription fees. Fishy?

from Approached by a publishing company, no money upfront, but will want 50% of subscription fees. Fishy?