Can I move from company B to company C while my H1b petition is still pending?

I left company A’s job on Feb 3 and joined company B on March 6 (H1B receipt date - regular process). Now a much better company C (very reputed) also offered a job to me around the same timeframe (within the 60 day grace period) but the negotiations and all their background checks took a long time and I have passed the 60 day grace period. They will mostly file LCA (at the end of April). Can I still go ahead with company C’s petition and join them on receipt? Would it be best in that case to ask company B to withdraw their pending petition? What happens if in the mean time company B’s petition is RFE’d or denied since I’m no longer there? Does USCIS throw out B’s petition and only process C’s? OR do they insist that B be approved first? Company C’s attorneys have said everything is ok to go, but I do need a second opinion since there has been some uncertainty over the new rules from Jan 17

I think it would be fine if you submit A’s approval notice and B’s transfer receipt, along w/ B’s payslips (Mar 6 onwards). This would show that you were back in status from Mar 6 and have been in status since then.

60 day clock stopped the date you joined B and they applied for H-1 petition.

Thanks a lot! If employer B petition for any reason is denied will it impact the employer C petition as well?

If the I-94 has not expired, then B’s denial will not impact C’s petition.

Thank you so much for this answer! Just 1 more query. My H1b from employer A is revoked now. Would I-94 be valid or does that get revoked as well?

I-94 is still valid, and you are still in status as B’s petition was timely filed.