** UBS Securities says advertising campaigns are being paused or delayed, but not yet canceled, as U.S. trade policy uncertainty is making it difficult for marketers to set business plans

** In Q1, ad budget growth started to deteriorate in February

** Advertisers are increasingly reallocating budgets to performance-driven campaigns from brand awareness - brokerage

** There is migration of budgets out of smaller platforms into larger; Meta META.O and Alphabet's GOOGL.O Google are well-positioned to benefit from this shift

** But UBS reduces GOOGL's 2025 and 2026 revenue forecast by 1% and 2%, respectively, and GAAP EPS by 6% and 11%

** Brokerage says, "search is likely to be the last place to lose digital budgets due to its proximity to consumers in a buying mindset"

** UBS reduces META's 2025 and 2026 revenue forecast by 2% and 4%, respectively, and GAAP EPS by 8% and 10%

** GOOGL up 2.6% at $156.85; META down 0.8% at $541.74; Pinterest PINS.N down 0.5% at $26.08, Snap SNAP.N up 1.5% at $7.95

(Reporting by Jaspreet Singh in Bengaluru)

((Jaspreet.Singh@thomsonreuters.com ; https://twitter.com/i_jass))