Updated from 2:40 p.m. EDT

Publicis

SA, the French advertising company, is expected to announce as early as Tuesday that it has agreed to acquire

Saatchi & Saatchi

(SSA)

, the British-based advertising agency.

Shares of

Saatchi & Saatchi

(SSA)

soared 30% Monday after it said it was in negotiations that could lead to its sale.

Although Saatchi did not identify its suitor, several news organizations including

TheStreet.co.uk

, the British affiliate of this Web site, reported that Publicis was making an all-stock bid for Saatchi valued at about $1.5 billion.

The deal would be the latest in an industry that has been roiled by a recent wave of consolidation. Last month,

Young & Rubicam

(YNR)

agreed to be acquired by the

WPP Group

(WPPGY)

of Britain, and earlier this year

Havas Advertising

agreed to buy

Snyder Communications

(SNC)

.

Saatchi's American depositary receipts jumped 7 11/16 to close at 33 1/16 Monday.

An agreement by Publicis to acquire Saatchi & Saatchi would come just weeks after the French made a failed attempt to buy Young & Rubicam.

Saatchi said earlier Monday that it had been approached by another company, and that the talks "may or may not result in a merger offer being made."

Other possible suitors including

Grey Advertising

(GREY)

and

Havas Advertising

, either declined to comment or denied that they were in discussions to acquire Saatchi & Saatchi.

The news involving Saatchi comes in the midst of management

turmoil at one of its biggest clients,

Procter & Gamble

(PG) - Get Report

, the Cincinnati-based packaged goods giant. That company ousted its chief executive earlier this month and warned that profits in the next two quarters would miss forecasts. P&G is also reportedly seeking to reduce the fees it pays its ad agencies, perhaps as soon as July 1.