Many rumors (1, 2, 3) presented the possibility that the Taiwan Smiconductor Manufacturing Company to open a factory in the United States to produce processors for Apple, replacing Samsung.
However, Morris Chang, CEO and President of TSMC, told the Taipei Times that although they are actually considering building a new factory in the USA, it has nothing to do with Apple. He also stated that the investment for this factory is around US $ 10 billion.
The United States is one of the places we are considering. However, this has no connection with Apple.
Even with that statement, Apple's plans to take part of Mac production to Uncle Sam's land remain standing. A possible partner for this endeavor is Foxconn itself.