In the auto manufacturing industry, this is generally a very low threat. Factors to examine for this threat include all barriers to entry such as upfront capital requirements (it costs a lot to set up a car manufacturing facility!), brand equity (a new firm may have none), legislation and government policy (think safety, EPA and emissions), ability to distribute the product (Alfa Romeo has been out of the US since the early 90s largely due to the inability to re-establish a dealer network. But if you are looking at Singapore, for example, only one Alfa Romeo dealer is needed!).