H1B - Can I work for two companies for a few weeks?

[jamesCovits]

I have an H1B and work for Company A.
I recently have accepted an offer from Company B, and Company B has been processing my paperwork to extend my visa.

Although I am leaving Company A, there are some tasks that Company A would like me to complete before I leave them completely.
However, Company B would like me to start working as soon as the paperwork is complete.

Is it possible for me to work for both Company A and B for a week or two (given that Company A will not terminate my H1B right away)?

[shervin143]

Nope. That is against the H1B regulation. Your year-end W2s should not overlap between two companies unless the H1Bs are filed as concurrent H1B which won't be in your case.