(John Kemp is a Reuters market analyst. The views expressed are his own) * Chartbook: tmsnrt.rs/3qx4yyE LONDON, Jan 18 (Reuters) - Hedge funds boosted their bullish petroleum positions last week, focusing on crude and gasoline, betting on continued output restraint by OPEC+ and an early resumption in domestic business activity. But they sold middle distillates, likely reflecting concerns about a slower re-opening of international borders and return to aviation, even as coronavirus vaccines are rolled out (tmsnrt.rs/3qx4yyE). In total, hedge funds and other money managers purchased the equivalent of 51 million barrels in the six major petroleum futures and options contracts in the week to Jan. 12. It was the largest wave of buying for seven weeks and takes the total since the middle of November to 450 million barrels, records published by ICE Futures Europe and the U.S. Commodity Futures Trading Commision show. Most of last week’s purchases established new bullish long positions (+41 million). There were also some repuchases of previous loss-making short positions (-10 million). Buying was concentrated in Brent (+25 million barrels) and NYMEX and ICE WTI (+22 million) with smaller purchases in U.S. gasoline (+7 million), and sales of both U.S diesel (-1 million) and European gasoil (-2 million). Funds hold a combined position in the six contracts equivalent to 805 million barrels, up from 356 million at the start of November, before successful vaccine trials were announced, though still down from 970 million this time last year. Bullish long positions outnumber bearish short ones by a ratio of more than 5:1, up from less than 2:1 in early November, but down from 6:1 or even 7:1 at this point last year. The combined position is in the 77th percentile for all weeks since the start of 2013, while the ratio is in the 72nd percentile. There is still some scope for bullish position-building, but the short-term balance of risks is starting to shift towards the downside. In Brent, flat prices and especially calendar spreads have eased significantly since Jan. 12, indicating a temporary hiatus in buying, and possibly even light profit-taking, as some of the froth is taken out of the market. The gasoline position appears particularly lopsided, with longs outnumbering shorts by almost 10:1, a ratio in the 84th percentile for all weeks since 2013. By contrast, the position in distillates was not stretched, with longs outnumbering shorts by only 2:1, a ratio in just the 52nd percentile. Related columns: - Rapid oil price rise divides fund managers (Reuters, Jan. 11) - Hedge funds end 2020 with lopsided oil position (Reuters, Jan. 5) - Oil sees more fund buying, but risks shifting (Reuters, Dec. 7) - Positive oil outlook draws in fund managers (Reuters, Dec. 1) (Editing by Barbara Lewis)