The English city's unheralded football club is on the brink of becoming league champions for the first time in their 132-year history, with just three defeats all season.
Microsoft saw its shares fall 2.6% on Monday.
World Cup sponsors are in an awkward position, experts said, because they are under pressure from consumers to distance themselves from any corruption, but such sponsorships are lucrative in the long term.
The deal would involve Pfizer paying with 11.3 of its shares for each Allergan share.
The United States Soccer Federation said in a statement on the new charges that its hosting of the 2016 Copa America Centenario tournament would go ahead as planned.
Eyewitnesses reported hearing a loud "bang" from inside the venue.
Nike Inc and some other big international companies face a grilling over their powerful role in Brazilian soccer.