(ShareCast News) - Go-Ahead slumped after JPMorgan Cazenove downgraded the stock and cut its price target to 2,768p from 2,879p."We continue to believe that Go-Ahead is well positioned over the long term, but ahead of next week's prelims we reduce our rating to 'neutral' from 'overweight' due to potential risks to FY16E earnings, specifically from rail and the GTR franchise."The bank said that given recent industry commentary, in the event of lower-than-expected profitability at GTR, it does not see other parts of the group completely making up for it in full-year 2016, meaning consensus reductions would likely follow.It said Stagecoach's recent first-quarter trading statement highlighted marginal declines in passenger numbers in its UK regional bus business, owing to bad weather over the summer, and JPM reckons some of Go-Ahead's bus businesses may still be experiencing problems associated with roadworks.JPM said Go-Ahead's cash conversion is sector-leading, and the conservative balance sheet should offer flexibility over the long term. However, in the short term, investors may get the opportunity to purchase the shares at a cheaper price, it added, noting that the stock is trading at a premium versus the sector.At 131 BST, Go-Ahead shares were down 4% at 2,477p.