My current company name has been changed in the US but the Indian subsidiary is using the same old name. I do not have any document to show a connection between the new US & old Indian company name. I also have B1 US Visa valid till 2017. What do I do for immigration check?
B1/B2 is a visitor/tourist visa. US immigration officers don't care what company you work for in India (unless there are some very unusual circumstances). You can enter the USA on a valid B1/B2 even if the purpose of your trip is different from that of your first trip to the USA (as long as you don't intend to violate the conditions of B1/B2).