From Jason Pisesky, “Incentive Effects of the New SBD Clawback” Canadian Tax Focus 4:4 (May 2018):
[Where a corporation earns ABI equal to its business limit] an extra $1,000 of rental income creates $1,307 of immediate tax in Alberta, as well as cash flow issues in certain situations. Changes in investment portfolios may be appropriate.
This harsh result is ameliorated by paying dividends, but that can be problematic because of the new split RDTOH rules.
Corporations might consider investing in less risky assets to generate less investment income or investing in growth assets to control better when returns are realized.