Can You Get a H-1b Transfer Before the Start Date

- Graduated with B.A. in Dec 2013.
- OPT valid: Feb 11, 2014 - Feb 10, 2015 (STEM not available).
- Currently employed as a paid intern at "COMPANY C" between Feb 26, 2014 - May 30, 2014.
- Expecting to start work at "COMPANY A" on June 23, 2014.
- Today (May 7, 2014), I heard from "COMPANY A" that "A" received a H-1B approval on behalf of me, and "A" will provide me with the H-1B approval once I begin the employment on June 23, 2014.

***Now the stressful part begins...***

- A week ago, I received a full-time offer from "COMPANY B" and "B" is willing to support H-1B. "B" doesn't know that "A" received H-1B Approval on behalf of me. I really want to work at "B" so I accepted an offer already.
- "COMPANY B" asked me to start the work on June 1, 2014.

Q> Is there any way I could safely TRANSFER my H-1B from "A" to "B", and begin my employment with "B" on June 1, 2014?
PLEASE HELP ME. If you know anyone who went through the same experience, please email me or msg me.

THANK YOU.

You cannot transfer a H1B visa before you're in status on that visa. Functionally, though, it makes little difference. If you have been approved for a H1B visa and counted against the cap, then your new employer can petition for an H1B visa without worrying about the cap; they can also use premium processing to get a quick decision.

I have B.A., which means my H-1B is subject to cap (one of 65,000 H-1B). I just spoke with my private lawyer, and she advised that I can transfer my H-1B from "A" to "B" even though I begin working at "A", under condition I have relevant legal documents and the H-1B case receipt number. But she also added that it is always best to actually having the original I-797 with I-94 attached to it, in order to make sure that the Case Number is actually mine.

Problem is that "A" sent me email yesterday that the company will provide me the H-1B Approval Notice (guess this is I-797?) once I begin work on 6/23/2014. Is there any good way to pursuade "A" or "A's corporate lawyer" to provide me, at least, H-1B case receipt number?

The petition belong to them. It is obvious that they have had others do just what you plan to do - take advantage of their filing to "reserve" a spot under the quota while pursuing other opportunities. What you have done is unprofessional; you cannot legally "pursuade" them to give you what you want.

Yes, and this whole things wags the dog. The hole point of this visa is not to find you a way to work in the US but rather it allows employers with specialized needs that can't be met by US employers to bring in workers who wouldn't otherwise qualify for work visas. I've pulled in about H-1B's in specialized fields over the years. I'd never had a worker jump ship on me before starting (in fact, because of our corporate environment, it was rare I'd have a worker, foreign or domestic, jump ship on me even after showing up for work).