It’s not a “risk”, it’s called “lose your H-1B”, and your OPT (if that’s your previous status) will only be effective til 09/30.
Updated the post. Planning to change after Oct and through H1-B visa transfer.
Transfer can be done prior to stamping. Done that.
How long does the transfer take ? If I plan to leave around October 15, will the current company be OK with it ?
If premium processing is still on, you should get to know the decision in 2 weeks. Your current company will not know a transfer has been initiated unless you tell them.
OP - I am also in the same situation. Hoping you've come to a decision, would this affect in any way getting H1B visa stamped ?
Any update on this what did u do?
You do realize, don't you, that your current H1B is petitioned by the employer whom you are desirous of leaving? And so, if your CURRENT employer withdraws your petition (which they should, per law, when you cease to be their employee), you will be left with NO H1B AT ALL? In short, you cannot switch employers before Oct. This is basic H1B 101
Updated the post. Planning to switch after Oct.
Really, stamping IS the final step of your H1B approval. And so, my comment above still holds. Having said that, I haven't gone through this personally, so perhaps someone who has, could help better. Am assuming here that you have access to an immigration lawyer, anyway.