** Shares of Bubs Australia BUB.AX fall as much as 12.1% to A$0.145, set for their weakest trading session since April 4, if losses hold

** The infant formula maker says strong USA performance in the first quarter partially offset by year-on-year reductions in other markets

** "Our China, Australia and Rest of World regions also faced stock availability challenges in the quarter," says co

** BUB logs negative first-quarter operating cashflow, also expecting to be operating cash flow negative in the second quarter

** Around 8.8 million shares change hands, 6.3x the 30-day average volume of 1.4 million shares

** YTD, stock up 65%, including the day's moves

(Reporting by Shivangi Lahiri in Bengaluru)

((shivangi.lahiri@thomsonreuters.com))