Assuming that you were not an "overstay" on your previously authorized H-1B with the former employer and you will be applying for the multiple entry B-1 NIV at a consular post, you may well qualify without prejudicing the NIV application by having been in H-1B classification previously. An H-1B petition is employer-specific and non-transferable (except in relation to specific corporate acquisition scenarios - i.e. successors in interest), but parallel H petitions, in some circumstances, can be filed by a new employer prior to the actual termination and departure of the employee from the former employer.
Answered on May 25th, 2012 at 8:43 PM