thanks! update:

下午发现paycheck上列了pension inquiry的800电话，it's managed externally. 问的结果是, state law规定，被并购公司的pension becomes vested and frozen immediately, no matter how long you have worked for the company.

And for the pension at the new, acquring company, your service at old company does NOT count toward the total AMOUNT of new pension(no double counting, as it's already vested at the old company), but for most companies, including mine, the service years at the old company counts toward the 5 years required for pension vesting at the new company. And the vesting part, as many pointed out, may vary from company to company.

They are sending me a statement regarding that.

Hope this helps.