Glad it worked out ...
Some comments / tips ...
You speak of a "deposit" ... you mean they deposited the $1 Million into an escrow? ... if so, the transaction is basically complete ... congrats
-or did they only paid a portion now? If so, be careful! Folks who do 7-figure domain deals generally pay straight away, and want to get the deal done.
Anyways, make sure you're doing the transaction via a *legitimate* escrow service (ie. escrow.com, greatdomains.com, or maybe Sedo.com - alternatively have a trusted party, such as an attorney, hold the funds; be careful if going the attorney route) before transfering the domain ... yes, I'm sure you know / doing that, but there have been cases of folks selling high profile domains being scammed, and having limited legal recource.
From an accounting aspect, assuming you still have a partner ... $1 Million / 2 = $500K less taxes ... ok, like no kidding...
However, the tax part is where things get more complicated and is often a detail overlooked ... how you structure/report the sale could be the difference of paying taxes of less than $75K to over $200K on a $500K portion.
To be clear, the sale is a winner, but be aware of how it's accounted for ... ie. your company books it as a long-term gain and you then take the bulk of the proceeds as a distribution ... and/or the company could choose to buy some other stuff (real estate, domains, etc) to reduce taxable income ... many ways of reducing tax liability - key is to research the options now so you're not surprised later on ... difference could easily be in the $100s of K!
Again, congrats
Ron
p.s. curious as what kind of company bought it ... PPC traffic broker, porn entertainment, cannabis related, government, etc ...?