The front view you have is distorted, the box is 2 x longer than the cards. When he 'cuts in half', the blade is actually at the end of the cards. Consider too, you can't cut cards so easily like that with a blade.
I don't think so. When he divides the box, you can see it is not twice as long as the cards were when shown. Have a look again. So I think it's something else, but what I have no idea. Of course he doesn't actually cut the cards.
When he gives the first view of the empty box, it is dark inside, ie partioned off. It's a double box, the cards only slide halfway through.
The box length is less than the length of his hand. Fingers are bent so limiting the length. That’s not the length of 2 cards.
When he pushes the cutter in it pushes the cards down and the bottom of the box opens. He raises the box a bit before he pushes the cutter in. His hand position hides the bottom of the box as it’s pushed down. He’s careful to cover the area under the box. When he pulls the cutter out the box lowers back to his hand. Towards the end you can see the bottom of the box has a groove around the edges so it can push down.
So I watched the video a 2nd time, the box is in two haves obviously, the 2nd half is shorter and already has a fake pack of short cards inside. The first half of the box is partioned off, when he inserts the cards you can hear the clunk when it hits the wall.
CNBC has this guy on from time to time, and there's no way this is a set-up because he has done this stuff on lots of other shows. Watch this. It's amazing. Meet the Wall Street Mentalist: