There are few other publicly known examples of Mr. Mueller using subpoenas.
Mr. Mueller dropped the subpoena after Mr. Bannon agreed to be interviewed by investigators.
Mr. Mueller could run afoul of a line the president has warned him not to cross.
Among the Trump Organization’s holdings are golf clubs, hotels and licensing agreements for the use of the Trump name on properties and other products.
The Trump Organization is not publicly held, making it difficult to determine where it receives its money and invests it.
A revealing comment about Russia by Eric Trump, the president’s middle son, also drew scrutiny when it emerged last year.
At the same time, Mr. Trump is considering whether to bring on a new lawyer to help represent him in the special counsel’s investigation. »