BUZZ-Weir: snaps 5-day winning streak on Citi downgrade
** Engineering co Weir down 2.7 pct, among top losers on FTSE midcap index, as Citi downgrades to "neutral" from "buy", cuts PT to 1200p
** Citi says it was premature in calling for a turn in US shale investment in Q3, expects US rig count to now be down on avg v expecting growth previously
** Weir rose on Tuesday after reaffirming FY expectations despite margin pressure
** Shares (Berlin: DI6.BE - news) down after five straight days of gains for co; 9th-top UK midcap faller in last 6 mths, -39% (until Thurs close) (venkateshasoumithri.mamidipudi.thomsonreuters.com@reuters.net)