The challenge with digital comics is that providers usually keep their numbers close to the vest; Milton Griepp of ICv2 estimated the total value of the digital comics market at $25 million in 2011.
If that's right, then comiXology had the lion's share of it. According to PEHub, a blog that tracks private equity and venture capital opportunities, "The comiXology platform produced $19 million in gross merchandise value in 2011, which is expected to jump to about $70 million in gross merchandise value this year."
Gross Merchandise Value is pretty much what it sounds like, the total value of merchandise sold through a particular site at the retail price paid by the consumer. The article also mentions that users have downloaded 77 million comics since the company launched its digital comics service.
If Griepp's numbers are accurate, comiXology owned almost 80 percent of the digital comics market in 2011. The growth number is even more impressive; if it's accurate, sales will almost quadruple in a single year. (It should be noted that Griepp is a member of the comiXology board of directors so he was privy to these numbers all along.)
The information came during comiXology CEO David Steinberger's presentation during the Software & Information Industry Association (SIAA) Conference; he also mentioned that the company may be looking for growth capital in the next six months.