Who owns the source code? Employee or employer?

I found these 2 articles discussing “who owns the source code” issue.

http://www.computerworld.com/s/article/print/9126595/Who_owns_the_code_Beware_copyright_pitfalls?taxonomyId=11&taxonomyName=Development

http://www.burgess.co.nz/law/copyright-ownership-and-software-development

The first article discusses the issues using US copyright law; the second is in the context of New Zealand. There are slight difference between the 2 laws with regard to Contractor/Customer relationship but the case of Employee/Employer is the same: without explicit agreement (contract), the Employer owns the source code.

In Singapore, it is the same: Employer is the copyright holder. This article briefly mentions it: http://www.guidemesingapore.com/incorporation/trademarks/singapore-copyright-law-introduction