This is a very broad question and the answers will be different depending on the type of company and the level of management. For instance, if it is a publicly traded company, then the share holders own the company. If it is private company, then a person can own the company. This makes a huge difference in terms of who owns the assets. In the former case, the management team does not own the assets (unless they own all the shares); in the later case, the management may own the assets, if they own a part of the company.
As for risks, they are the one that call the shots. This means the management makes the final decisions. So, they assume all the risks. They are the ones that are responsible. Moreover, the higher you go up in the level the management, the more responsibility you have.