What is the minimum required compatibility level to use parallel SELECT INTO?
In SQL Server 2014 parallel DML for the SELECT INTO statement requires compatibility level 120.

110:


  A SELECT INTO statement always creates a single-threaded insert operation.


120:


  A SELECT INTO statement can create a parallel insert operation. When
  inserting a large numbers of rows, the parallel operation can improve
  performance.


Note, that other resources on the web state false values for the compatibility levels. These statements are quoted directly from Microsoft documentation and have been verified experimentally by me.