Final answer:
Lowering the investment base tends to increase ROI, provided that it does not negatively impact net income, as ROI is calculated by net income divided by investment base.
Step-by-step explanation:
Reducing the investment base while assuming other factors remain constant will generally lead to an increase in Return on Investment (ROI). ROI is calculated by dividing the net income from an investment by the cost of the investment. Hence, if you decrease the denominator, which is the investment base, without altering the net income, the result is an elevated ROI percentage. This remains true unless the reduction in the investment base would, in some way, negatively affect net income.