The Munich-based firm, one of Germany's biggest industrial companies, had all but replaced the top of its sales and marketing teams, according to a report in Der Spiegel magazine, subsequently confirmed by the company.
Three top managers had already been fired, while about half a dozen more had been suspended and would be replaced in coming weeks.
They came under the spotlight in May when investigators swooped on 59 MAN sites and seven homes in searches that lasted about a week. More than 100 people were questioned.
Prosecutors said bribes totalling millions of euros had been paid both inside and outside Germany to secure the sales of trucks and buses.
The spokesman said the company wanted a fresh start in the tainted divisions. MAN had examined the situation carefully before taking the measures, he stressed. And he added the sackings were separate from any criminal proceedings.
Prosecutions are likely to go ahead, though not against the top managers in the company.