I'm not disagreeing that the total assets of the company decrease (book value). I am saying that the assets per share or book value per share (whatever you want to call it) are increasing and thats what we as investors want to see. Lets say Company A has 1000 outstanding shares at an issued price of $10 per share and then an additional $5000 cash on hand....Now on top of this lets say the $10,000 dollars that they received from issuing shares was put towards some MBSs to generate further income. They have total assets worth $15000 or $15 assets/share. Now lets say they take that $2000 of their reserved cash and spent it on shares at $8 a piece (bought 250 shares). There total assets now decreased to $13000 and there shares dropped to 750 for a grad total of $17.33 assets/share or BV/share.