Depends which position they held. At the highest level, ...since Nixon, but only because he ultimately held himself accountable in order to avoid the wrath of others. Trump took that same gambit the other direction, though, and proved that he was invincible.They should at least be subject to the same insider trading laws as everyone else.
But since when are politicians held accountable in the US?
If Pelosi wants to do some insider trading and get away with it, she could. Nothing will happen to her. And I realize that the source might not be very reliable, but it doesn't matter in terms of accountability. Everybody knows that any high profile congressperson could get away with virtually any financial crime.