CV drop and salaries

CV will drop when depositing money into your salary account because you have spent money...
Gaining and losing money
For every 20 iKr gained, your company value increases by one. For every 20 iKr lost or spent, your company value decreases by 1 iKr, except when investing money, purchasing zones, upgrading factories, and donating to Today's TO-player. 
The above is sourced from the main help files linked here.
Tycoon Online FAQ