The US National Security Agency (NSA) sought to spy on businesses in Europe via the German Bundesnachrichtendiesnt (BND) foreign intelligence agency's monitoring station at Bad Aibling in southern Bavaria, the tabloid reported.
Bild said it had seen two documents sent by the BND to the chancellery in Berlin in 2008 and 2010 to inform it of the NSA snooping.
The report is potentially embarrassing for the German government, which has always portrayed itself as a victim of spying by its allies, notably the United States.
Germany reacted with outrage at revelations in 2013 by fugitive US intelligence leaker Edward Snowden that the NSA was conducting massive Internet and phone data sweeps, including in Germany.
The revelations, which included claims the NSA tapped Merkel's mobile phone, strained ties between Washington and Berlin.
The documents cited by Bild refer to NSA attempts to keep tabs on telephone numbers and email addresses at EADS, the aerospace and defence group now known as Airbus, and Eurocopter, which now goes by the name of Airbus Helicopters.
'German help to monitor German companies'
"It was definitely known for years in the chancellery that the NSA tried, with German help, to monitor German companies," Bild quoted an unidentified source from the Bundestag (German parliament) NSA inquiry committee as saying.
"It is unlikely and would be highly unusual if the head of the chancellery would not have been informed about such an occurrence," the source added.
That post, which includes supervising the intelligence services, was held in 2008 by current Interior Minister Thomas de Maiziere, a conservative ally of Merkel's.
Bild said, again citing an unnamed source from the German parliamentary committee on the NSA, that Germany apparently chose to close its eyes to the information to avoid upsetting its cooperation with the NSA, especially on counter-terrorism.
"One said at the time 'we need the Americans' information, that's the way things are, we don't want to endanger cooperation'," the source was quoted as saying.
German news weekly Spiegel reported last week that the NSA spied on European companies for years with the help of German intelligence.
The American agency is believed to have provided the BND with mail addresses and mobile phone numbers which were then monitored by the Germans on behalf of the United States, Spiegel Online reported.