Marc-Oliver Frisch writes at The Beat:

The question whether the economy has any effect on DC Comics’ periodical output is increasingly difficult to answer. On the one hand, many titles not right at the center of the publisher’s big superhero line are losing units by the truckload, and new series debut with abysmal numbers — case in point in December: Vigilante. Then again, these are trends which have been visible for a while, so what we’re seeing may as well be a continuation of what’s been happening anyway, rather than the result of the current crisis. Of course, it could also be both.

That said, DC’s average periodical sales in the direct market recovered slightly in December, mostly thanks to an issue of Final Crisis and multiple entries by three high-ticket series: There were three issues of Batman and two issues each of Justice League of America and Justice Society of America. Average sales didn’t recover as much as you might have expected, however. One reason for this is the increasing decline mentioned above, another is that a number of series returned to a much lower level, now that the “Batman R.I.P.” event is over.

Vertigo and WildStorm’s average periodical sales were in decline again in December. Whereas the average Vertigo title remains in the 11-12K area, the average WildStorm periodical dropped to yet another historical low point, selling fewer than 9,415 units. We don’t know the exact number because multiple new WildStorm releases again failed to make the Top 300 chart — a rather more recent trend. Their number rose to four in December.

On a technical note, I should mention that the December chart includes books which shipped on January 2, 2009 — not because any of them were late, but because Diamond evidently felt more comfortable with that date. Originally, those titles were expected on December 31, which is presumably why they ended up on the December chart.