The Pentagon investigation only examined the single March 17 air strike, which took place at 8.24am local time.
An additional 36 civilians remain unaccounted for, it said.
Officials now say that ISIS had likely placed explosives inside the building, contributing to the deadliness after the bomb was dropped.
Iraqi and coalition forces did not know civilians were in the building and ultimately a strike was called in, US General Matt Isler said. The resulting blast, the Pentagon said, killed most of the 101 civilians inside the building and four others in an adjoining house.
The deaths occurred on March 17, when a USA precision-guided bomb struck a building believed to be housing two Islamic State group snipers, in a neighborhood called al-Jadida. Residents of the adjacent building, which was also damaged, he said, were ordered not to leave the night before the attack.
Isler said the United States and nearby Iraqi forces did not know there were civilians in the building or that it had been rigged with explosives.
"We call upon the global community and especially the United States to compensate the victims", said Nuraddin Qablan, deputy president of the Nineveh provincial council, as quoted by AP.
A USA military pilot, who spoke on the condition anonymity because of his active duty status, said the report's damage estimates for the initial airstrike were low and unrealistic. "Like in Mosul, there were women and children among them", Zakharova added.
Residents living in a neighbourhood in Mosul, Iraq, targeted by a USA airstrike in March have rejected findings of a Pentagon probe into the attack.
But the Pentagon investigation focused exclusively on the airstrike that hit at 8:24 a.m. local time.
It was likely the largest single incident of civilian deaths since the USA air campaign against IS began in 2014.
Iraqi officials and human rights groups feel differently. During the two month investigation coalition members visited the scene of the strike three times where they took measurements, photos and gathered soil samples, Scrocca said.
As of the most recent Centcom official tally, a total of 396 civilians had been killed since the beginning of the bombing campaign against the Islamic State group in Iraq and Syria almost three years ago.
Airwars, a London-based collective of journalists and researchers that tracks civilian deaths in Iraq and Syria, claims a minimum of 3,350 people have died in coalition strikes.
The 105 figure from the March incident would push that number beyond 500.
"The Coalition will continue to degrade, disrupt, and dismantle ISIS structure, as well as exert pressure on its senior leaders and associates across multiple networks throughout Iraq and Syria", it said.
USA -backed Iraqi forces are closing in on the last IS held neighborhoods in western Mosul nearly three years after the extremists overran almost a third of Iraq in 2014.