** Hong Kong shares of Baidu 9888.HK fall 4.6% to HK$84.5, on track for the biggest one-day pct drop since April 7

** Stock is the biggest pct loser on Hang Seng Tech Index .HSTECH, which is up 0.7%

** U.S.-listed stock BIDU.O fell 7.5% on Wednesday

** Jefferies keeps "Buy" rating on Baidu's U.S. shares but cuts price target to $110 from $120 on expecting Q2 Baidu Core revenue to decline by about 3% YoY vs prior estimate of 1% YoY decline to factor in emphasis on user experience with an increase in the percentage of search results covered by generative AI

** Jefferies expects Q2 Baidu Core online marketing revenue to drop by 16% YoY vs 10% decline expected previously, and Q3 online marketing revenue to drop by about 18% YoY

** Nomura keeps "Neutral" on the stock but trims target price to $93 from $95, saying search advertising falls victim to Baidu's AI search drive and expecting Baidu Core's 2Q revenue to drop due to weaker ad revenue

** YTD, Hong Kong stock up 4.1%, U.S.-listed shares up 2.4%

(Reporting by Donny Kwok)

((donny.kwok@thomsonreuters.com))