The H1B transfer is quite tricky once you pass the 6th year extension. Many would assume that because they have already obtained a previous extension beyond six years, they will be able to carry this time to the next company to which they are transferring. But that is not really true because every transfer will be considered as an extension and as such you need to have a valid I-140 or pending 365 days labor certification for an H1B transfer to be approved. This video explores the issues relevant to the transfer when the I-140 is at risk.