Return on shareholders funds
From ACT Wiki
(ROSF).
A measure of how much profit is enjoyed (or expected to be enjoyed) by ordinary shareholders, compared to the book value of their equity investment made.
Profit is measured as profit attributable to ordinary shareholders.
This is profit after tax, less any dividends payable to the holders of preference shares (preference dividends).
ROSF is calculated as:
Profit attributable to ordinary shareholders / (ordinary shareholders funds)