In larger corps, at least, they will have salary ranges for each staffing level. It's common for these ranges to be very wide. For example, I've commonly seen the upper end of a lower staffing level be the same or higher than the lower end of a higher staffing level. It's not unheard of that a junior employee will make more than a senior employee. That's why corporations like to keep salary information obscured.

Plus, unless you want the job very badly, it (usually) doesn't hurt to ask.