Your 'Organisation Value' is the value of all of your individual 'Hospital Values' combined. The hospital value for each hospital is determined by these factors:
Cash - the amount of cash you have (either positive or negative)
Profit Factor - a value based on wether your hospital is assumed to making a profit (either positive or negative)
Physical Assets - the value of all items and machines placed in your hospital (always positive)
Outstanding Loans - the value of the loans you took (always negative)
On the map you can scroll around to see the values for each of your hospitals. When playing in one of your hospitals, the hospital value is displayed on your 'Finance' page in the overview. To go there, press
to go to the menu, press
twice to go to the tab marked with a yellow dollar sign, click the green 'Overview' button and then use either
or
to go to the 'Finance'-page.
This achievement should come naturally as your play through the different hospitals. If you like to unlock this earlier, just have your most profitable hospital run for a while to increase your cash.