May be they would have to risk a trial to convict both but he would plea guilty to protect his wife. If the state believes he was the most responsible then they may judge a guaranteed conviction without the cost of trial to be worth it.
The wife (and family) lost 2.6 million, plus her job, and the husband - so it's not like she got away with something, just avoided the worst of the punishment.
If they kept the $2.6M in a liquid saving account just for cases like this one, yeah, that wouldn't be so bad. But I don't expect that's the case and in practice that could mean for example losing her house.
>Insider trading violations may also include "tipping" such information, securities trading by the person "tipped," and securities trading by those who misappropriate such information.
It sounds to me like even giving information to someone if you know that person will trade is illegal.