This should be long enough: XM (NSDQ: XMSR) and Sirius (NSDQ: SIRI) have extended their merger agreement to May 1, as the clock continues to tick on regulatory approval. Both companies have said they expect approval in the near future, but the agreement had been set to expire tomorrow, so they had no choice but to extend. Last week, the agreement to merge turned a year old, a year in which numerous rumors of an “imminent approval” were proven wrong. Release.