BUZZ-Soco International: worst performing UK mid-cap after JPMorgan downgrade
** Oil producer's shares down as much as 3.7 pct after JP Morgan downgrades stock to "underweight" from "neutral"
** Downgrade comes after stock's 37 pct rise from its March lows when disappointing results hit shares hard
** JPMorgan (LSE: JPIU.L - news) says the outlook for Brent oil prices, which it sees stuck in a $50-$70/barrel range in the medium term, presents a grey area for E&Ps and those with stretched balance sheets are likely to underperform
** On Soco, JPM sees a risk to next month's dividend payout as free cash flow remains constrained at current oil prices
** Stock top loser on FTSE 350 Oil & Gas Index, with a tenth of its avg daily volume going through in the first 20 minutes of trade
** Oil & gas the worst performing sector across UK large & mid-caps on the day. Cairn Energy (LSE: CNE.L - news) falls 1.5 pct, Tullow Oil falls 1.8 pct (venkateshasoumithri.mamidipudi.thomsonreuters.com@reuters.net)