ZF Offers to Buy TRW

German transmission maker ZF Friedrichshafen AG has made a preliminary overture to buy TRW Automotive Holdings Corp., according to Bloomberg News, which cites unidentified sources.

TRW confirms it has received an offer but did not identify the bidder. The company and ZF have declined to comment on Bloomberg's report.

The news service says the companies haven't discussed a price. But ZF values TRW at $11 billion-$12 billion, according to one of Bloomberg's sources.

Talks are in an early stage. If they result in a deal, the merger could be ZF's largest ever and the auto supplier industry's biggest takeover since Continental AG acquired the VDO Automotive unit of Siemens AG seven years ago.

According to their annual reports, ZF and TRW posted sales in 2013 of $22.9 billion and $17.4 billion, respectively. ZF makes driveline and chassis systems. TRW specializes in airbags and electronic safety and driver-assist systems.