According to Finnish gaming magazine Pelaaja, Microsoft will be holding a Spring showcase on February 29th (hey, that's not Spring!) and there, Halo 4 will be shown to the press.
343 Industries have been quiet on Halo 4 details since the E3 2011 reveal, so more information is welcomed.
In previous years, Microsoft has used their Spring showcase to display upcoming games such as Gears of War 3 and The Gunstringer.
We haven't received our invite yet, but we went last year. Expect GR to invade the event, per usual.