Salaries (Golden Rainbow)

I've been increasing my salary for corporations that are low on hiring but it seems that they just keep losing workers. Why is this?

You need more unemployed workers to fill the jobs.

Check that you have enough workers in each category. If you only have 100 execs, but a corp needs 200, then that corp will only hire at 50% across all workers categories even if 100% are available.

This advice is of course excellent, but I might add that it may presume state corps, you dont say which corps.
If the short corps are in your enterprise then you need to look at the countries the corps are in. Salaries need to go quite high to negate shortages and, in particular, C3 countries can screw your corps up so consider moving them. Contact presidents of countries with worker shortages and ask them to improve the situation.