There's been a lot of speculation about what the opening price of each new company will be, but none of the discussion I've found convincing because everyone's been pretty up front about it being conjecture. 

Personally, I think the answer is in the "when issued" shares for both companies that will be traded on Monday and Tuesday on the NYSE only. I looked up what when issued shares are all about and it seems that they're designed to reduce initial volatility around authorized but as of yet unissued shares of a new entity, which is exactly the case with LAC's separation. 

So certain investors, and I have no idea who, will be able to trade these WI shares for the two days before we all get access, and they will arrive at a price for each company's shares that they are comfortable with, and will presumably be in the ballpark of what the larger market will feel when full trading opens on Wednesday. As I understand it, these prices will inform the initial bid/ask prices during premarket action on Wednesday. 

I am very excited to watch this separation play out on the markets.

When Issued (WI): Definition, How It Works, and Example