Hi, I have an offer from Facebook London office as an E5. However I would like to work in US for a couple of years due to personal requirements. Have you seen anybody get an of offer for FB UK but has joined in US office ? I would require work permit/visa for either places anyways.
You can join to FB UK and then move internally.
Will I be able to move within a few months ( maybe 5-6 months ) of joining or do I have to wait for a longer period ? Also, it looks like FB does not change the RSU during transfer from UK to US as the offers in these countries seem to differ a lot in terms of RSU given. Do they recalculate and increase/decrease the RSU in case of internal transfer?
No. Only base will increase or decrease.
Can't hurt to ask but generally much harder to get a US work visa than UK.