If you're a software developer and you're part of the "IT" department, then you're a liability. Your code is a necessary evil.
If you're not part of the "IT" department, then you're working in a product-oriented environment where the company is selling your code (either as a good or as a service) or otherwise making money from the code. In that case, your code is an asset.
I've always understood it as functionality is an asset and code is a liability. The company wants and uses the functionality to make money. Code has to be maintained, has bugs, etc. Your goal should be to provide the required functionality while reducing the costs incurred by your code.
If you're a software developer and you're part of the "IT" department, then you're a liability. Your code is a necessary evil.
If you're not part of the "IT" department, then you're working in a product-oriented environment where the company is selling your code (either as a good or as a service) or otherwise making money from the code. In that case, your code is an asset.