Market transparency, in its most succint form, refers to the level of current trade information revealed to the public by market makers. We analyze the effect of market transparency on the outcomes of postedoffer style B2B markets under both stationary and non-stationary demand conditions. We find that sellers on average can extract significantly higher surplus than buyers, yet the difference decreases with increasing market transparency. Also, poor price-tracking ability of the posted-offer market after an external demand shock hurts buyers only. Seller profits are much less sensitive to the shock compared to buyer surpluses.