Although RHT exceeded both revenue and earnings estimates for the quarter, some people apparently focused on billings:
"On the minus side, Schwartz was disappointed by the $177 million in new
billings that Red Hat reported, which fell short of the $189 million he
was anticipating." -- Red Hat revenue
I'm not sure that was entirely accurate based on the transcript, -- Earnings Call Transcript
"Our billings proxy for the quarter was $177 million... In addition to seeing the typical decline from Q4 to Q1, our billings proxy was influenced by the fact that the percentage of one year deals increased 80% and the average deal length was 19 months as compared to 24 months of recent quarters."
.. but that was the way it was interpreted.
On the other hand, it could simply be a case of "sell the news", since a lot of the numbers were already expected and "priced in".
Who can really say in these markets. :-/