Harris Associates, one of the largest shareholders in security firm G4S
The opposition comes as Kames Capital, also a top ten shareholder in G4S, said on Monday it backed the 5.2 billion pound proposed takeover, in contrast to opposition already mounted by several fellow investors.
Despite the fact we have a great deal of respect for Nick Buckles and the G4S management team, we cannot support the acquisition of ISS under the stated terms and have voted no, David Herro, Harris' chief investment officer, said in a statement posted on its website.
Harris owned 4.93 percent of G4S as at August 26, according to Thomson One data.
Kames said in its statement it had met with G4S' management and supported the bid.
We believe the underlying business is very strong. We believe the deal will go through and we believe the combined group will be well positioned going forward, the asset manager formerly known as Aegon Asset Management, said.
Kames owned 1.6 percent of the company as at Sept 1. according to Thomson Reuters data,
On Sunday, Britain's Sunday Telegraph newspaper reported that fellow investors Schroders
Shareholder Parvus Asset Management has led opposition to the takeover, calling it an untested vision that it would not support.
Shares in G4S have lost around 15 percent since the proposed deal was announced -- partly due to the dilutive impact of a planned 2 billion pounds rights issue to help fund the deal. Shareholders are due to vote on November 2.
(Reporting by Tommy Wilkes; editing by Sinead Cruise and Hans-Juergen Peters)