By Chris Dorrell US equities have gone on a remarkable run since last October, leaving the FTSE 100 and other British markets lagging behind. After eking out a small positive performance this week, the S&P 500 has now climbed in 16 of the last 18 weeks, the first time this has happened since 1971. It has climbed 29 per cent over the past 12 months and 7.5 per cent year-to-date. “We are in rarefied air in terms of the relentless risk rally since the end of October,” Deutsche Bank’s Jim Reid said. The S&P 500’s remarkable run mainly stems from bets that the Fed will start cutting interest rates …