Genuinely asking, a real world situation would be cool. It seems like this would happen most when ex-employees try to compete with the large company.
At the opposite end of the spectrum think of a company like Intel investing into WiMAX. Developing that standard was not cheap, but almost by definition it was something that required disclosure of the end result. Intel can try to recoup the initial investment by selling chips implementing the standard, but competitors can always undercut them on price because they didn't have to spend any money coming up with the initial design.
There is a lot of technology that's much easier to reverse engineer than it is to develop. Especially with software, where it's often very easy to dig out a copy of the firmware from a competing product and decompile it.
You might think this kind of stuff doesn't actually happen, but in the 1990's American companies hated working with the Chinese precisely for this reason. They'd take an American product and copy it right down to the silk screening on the PCB's, and sell the result for cut-rate prices.
And the world is arguably a better place now that the Chinese can make super-cheap parts and clones of American designs and sell them to people who couldn't afford them otherwise.
We may have lost some of Shakespeare's plays because he had to be so secretive with his work, since he had no other legal protection from people just copying the stuff and putting on their own plays.
[1] Last chapter of the recent book "Imagine" by Jonah Lehrer