"That was an organized group of 19 perpetrators executing a carefully prepared plan of action," Manley reminded. "In Canada this week, we saw solo individuals with addiction and mental health issues."
He went on to say, it was critical to note the differences; because he feels it would be a mistake to draw definitive conclusions about current events based on what happened in 2001.
Read More Shooting in Canada was second attack in just 3 days
Of course, investors should always remain vigilant. Given the tensions in the world, Manley said, unfortunately, another attack could happen again. "We're seeing a repeating pattern of young men who are Western born and educated, who have become radical, because of exposure to radical Islam."
However, if you're making substantial changes to the way you invest due to the Canada attacks, commentary from Manley suggests that's probably ill-advised.
"I don't find it nearly as alarming as 2001," Manley said.