We knew it would have to heat up sooner or later. Silicon Alley Insider reports (via 24/7 Wall St.) that CNBC is pressuring execs and regular commentators to choose sides :

In a note to Fox producers an executive at Jefferies & Co. said he could not appear on the new network without losing his place on CNBC. Arthur R. Hogan, the Director, Global Equity Product at the investment bank wrote Fox "CNBC has put pressure on me not to do spots for any other business news stations."

CNBC executive editor Nick Dunn must not think he can compete with Fox head-to-head. In another email quoted by "Inside Cable News" he wrote a guest "Saw you on the new network. Please don't make that a regular thing."

This despite the fact that a NYSE source told Silicon Alley Insider, "there's barely a monitor in the building tuned to FBN anymore."