[altdataseller]

Because it’s not exact. Nobody knows how much your stock/options/RSUs will be worth x months from now. But they know what your base salary will be.

Also, if I’m a candidate and the company has to tell me a number, I do NOT want to know the “total comp” because it might be 90% lotto tickets (ie startup options) and 10% base salary. Unless they explicitly break it down, I rather know the base salary

[sokoloff]

It's not even clear what they're worth at the moment of granting. There are multiple models for options valuation which have to be layered on top of multiple models for private share valuation.

[zerr]

The law could require listing of base salary, nbr of stocks/options/whatever, any other benefits such as PTO.