** Advertising tech firm Trade Desk's TTD.O shares fall 4.3% to $24 premarket

** Stifel downgrades to "hold" from "buy," cuts PT to $26 from $48, still implying a 3.7% upside to stock's last close

** Rosenblatt cuts to "neutral" from "buy," cuts PT to $25 from $36, implying a 0.3% downside to stock's last close

** French advertising giant Publicis Groupe PUBP.PA told clients it no longer recommends TTD for digital media buying following an audit - Ad Age report, March 17

** PUBP claimed the audit revealed fees charged beyond what the master service agreement allows - Ad Age

** Stifel expresses concerns about how conservative TTD's 2026 estimates are if co loses clients after PUBP's audit, "and perhaps other agencies may follow suit in a similarly public fashion"

** "We're aware of questions related to a Publicis’ audit process. Any notion that TTD failed an audit is not true" - TTD

** PUBP did not immediately respond to a Reuters request for comment

** Avg. rating of 38 analysts is "buy;" their median PT is $32 - data compiled by LSEG

** TTD closed down 7.4% on March 17; up to last close, TTD had fallen 34% this year

(Reporting by Anhata Rooprai in Bengaluru)

((Anhata.Rooprai@thomsonreuters.com))