Legally yes but highly unlikely.
In the United States, employers are not prohibited from
double-checking job applicants' quoted salary figures. If you provide
a public or private employer with information about the compensation
that you've received in the past, you should expect its hiring
department to contact your previous employers and confirm that you're
telling the truth. Before deciding to proceed with a new hire, most
selective employers will take this step.
However, your previous employers might not provide any information to
your prospective employer. Unless they've been issued a subpoena,
U.S.-based employers are under no legal obligation to disclose any
information about current or former employees. In fact, most employers
specifically forbid their human resources departments from discussing
such matters. In most cases, these departments will simply confirm
your dates of employment and refuse to give out any additional data.
Law reference for US:
The reason most HR departments don't disclose this type of information is it can be a biased point of a reason not to hire. Also think of the ramifications of there being a mistake of the old employer quoting the wrong salary and the person doesn't get the job. The potential new employer says I am sorry you make too much... Now there is a problem. The old employer would rather break ties as quietly as possible. Also, in my own experience no information with a past employer has been verified; however references have been checked.
Now as far as what you can bargain for I would recommend:
- Look up the firm on glassdoor.com or a similar website. See what current employees make there. This will give you an idea if you are at a similar rate, above, or below what they currently pay.
- Glass door also allows you to look for positions in the same city and/or state. See what the average of the same position in other firms are.
- Put into consideration other benefits like profit sharing, 401K, and similar benefits into perspective. Does this employer pay for things like additional schooling and training?
- If all else fails, ask for $5K to $10K above what you currently make. If you have experience and unique skills make that apparent at the interview. As stated most companies are trying to keep payroll down, but if you are a rock star and they are indeed a "serious" company they will pay for good talent. If they are not then asking 10K over and bargaining down to $5K gives you something to work with. Remember you want a career where you aren't looking for the next best thing.