Ad slump thumps regional sports nets.(Fox Sports Networks L.L.C.)(Brief article)

THE GROWTH TRAJECTORY OF REGIONAL sports networks flattened a bit in 2009, as the advertising slump reduced overall revenue growth by nearly four percentage points, according to a report by SNL Kagan.

Total revenue for the RSNs was $4.64 billion in 2009, according to Kagan, which began tracking the networks earlier this year. That represented a 6.6% increase, down from the 10.5% increase the networks enjoyed in 2008 and the 14% rise in 2007.

In a note, Kagan senior analyst Derek Baine said the ad slump and a slowdown in subscriber growth (most of the networks are fully distributed) were the main culprits. That aligns with an earlier Kagan report estimating RSN ad …