Say you own 100% of a company whose fair value is $100 dollars. I give the company $900 and in exchange it issues me enough new shares that I own 90% of the company. Now you own 10% of a $1,000 company, with exactly the same number of shares as before, and your shares having the same fair value as before. Now this does assume that controlling stake of a company is not really worth anything, which is theoretically true if none of us is doing illegal-if-not-particularly-easy-to-prove screw-over-minority-shareholders type stuff.

Not to say there is never any funny business: with private companies who don't have a market for their stock the 'fair value' is not obvious and you can play games with that number to dilute away the ownership of people who don't have board seats.