AP reports that XM and Sirius have agreed to merge. In other words, Sirius is buying XM shareholders out for 4.6 shares of Sirius for each share of XM, which is valued at $4.5 billion.

Sirius CEO remains the chief executive of the merged company. XM chairman Gary Parsons remains chairman.

Stern federal scrutiny is expected.

The obvious question is whether XM hardware will continue to be supported.