One can access the WSIB's 2017 annual report in pdf form here.  The highlights of the report include the following pieces:

• premium revenue is down 3% from the fourth quarter of 2016 to the fourth quarter of 2017, with premiums themselves off 10% but offset partially by 7% decrease in payouts for employer incentives
• net investment income was way up to 3.5% return on investment due to a stronger market
• total revenue, premium and investment, was over three times the amount of claims payments; claims payments have fallen 6.3% since 2013.
• the funding ratio improved from 87 to 96 per cent

In summary, the WSIB is in a good financial posiiton, employers have had several years of declining premiums and injured workers all too often end up poor.  .