Q:

Does my employer own code I write at home using the Visual Studio license from work?

Simple question, maybe not an easy answer: my employer gave me an MSDN subscription linked to my home hotmail account.
Can I download Visual Studio and write code at home with this license? I would be working after business hours on my own personal projects.. Would my company own the personal project because I used their Visual Studio license?
edit: just to be clear: my personal project is a video game, and my company does not make games, and in fact is in a completely different industry

A:

If the code is unrelated to your employment you own the copyright no matter if it is written in Visual Studio, on a piece of paper or tattooed on your butt. In the same way a sculptor owns the copyright in their sculpture even if they use someone else's chisel.
Using Visual Studio in this way may, however, violated your contract with your employer and/or their contract with Microsoft. Why go there? Visual Studio Community is free.

A:

This would be an interesting stackexchange post to read. Not much legal content here but probably the same situation.
For the sake of a good legal argument:
Focussing on work for hire, since employer-employee relationship is clear and under no controversy here.
It is well settled law that employer own's the work product and can't have any claim on personal projects. In US, UK or common law the employer is treated as the first owner, but not deemed to be the author. Whereas in Civil law jurisdiction like Germany the ownership rights are firstly linked with the author and employer gets the ownership rights by assignment or contract. 
Common law policy cites reason for first ownership to employers because employers provide infrastructure and facilities so that creative works can take place. This is seen as contribution of employers towards production of new works. Also they are in better position to market and exploit the product. And further to cut the transaction cost for assignment of rights like in civil law. Employees are rewarded by pay, continued employment, promotion etc. [Source: Bentley & Sherman]
The only test for this proposed question is to see whether a work is produced in the course of employment.
It does not necessarily means the office working hours or produced at home with personal resources.
Missing Link Software v. Magee [1991] FSR 14: 
An employee wrote software outside work time and on his own equipment. Court found 
it to be in the course of employment and employer was given the ownership rights. 
Reasoning: Employee was hired to write programs of the kind in dispute. It fell within the scope of tasks he was employed to carry out and he was employed at the time of writing it.
As I also said the area/project for which you are writing program, its proximity  with the employer's business and your duties at employment are going to be a major factor.

A:

This will depend on jurisdiction, and on your employment contract.
In Germany, if you are a regular employee (abhängig Beschäftigter), then by default your employer owns all the rights to use to works you produce "to fulfill the duties imposed by the employment" (in Erfüllung seiner Verpflichtungen aus einem Arbeits- oder Dienstverhältnis, §43 Urheberrechtsgesetz).
So anything you produce as part of doing your job belongs to the employer(*). Conversely, if you do anything not related to your job, it's yours. It does not matter if you did it on company time or using company equipment - that may violate your employment contract and may get you fired, but does not by itself assign any rights to your employer.
(*) You still retain authorship rights, such as the right to be named as the author. These rights are inalienable in Germany (unlike e.g. in the US). However, the employer receives all rights that are practically relevant, such as the right to use and copy.

Of course, in practice the boundary between "job duty" and "private work" may be a bit blurry, so it's best to play it safe and keep private stuff at home. But using a software license provided by your employer will not give them any rights to the work you produce.

