The value of Fortescue shares – linked to millions of Australians’ superannuation accounts – could take a hit with a value downgrade from Morningstar.The rating agency issued a fair value downgrade of 4 per cent on Fortescue stocks on Wednesday to $15.50. Shares are set to open the day’s trading at $18.08.Morningstar points to forecast lower steel sales in the near term and cost blow outs at Fortescue’s beleaguered Iron Bridge project in northern WA.Analyst Jon Mills said in the note Fortescue was being hit with multiple issues.“Cost inflation and lower volumes meant unit cash costs rose 19 per cent in the quarter, to US$19.40 per metric ton, while problems at Iron Bridge persist,” Mr Mill said,“Despite recent declines, shares trade 16 per cent above our intrinsic assessment, likely due to the market expecting strong iron ore prices of around US$100 per metric ton to continue for longer than we do.”Fortescue is scheduled to release full-year financial results to the ASX on August 24.The downgrade from Morningstar is in large part due to the miner’s Iron Bridge project in the WA Pilbara.At Iron Bridge, workers use a high-energy method to turn low-grade ore into a premium magnetite concentrate.Iron Bridge’s initial 2019 budget of $4bn has blown out to $6.2bn, as Fortescue struggles to ramp up its magnetite plant despite the site sitting next to Fortescue’s own mine, and own rail line which runs to the company’s port.Last month, Fortescue was forced to write down the value of the project by $1.1bn, and withdrew its target of full-capacity production by 2028.Morningstar deems Fortescue has no durable competitive advantage, translating to a “no-moat” rating.“Margins are well below industry leaders BHP and Rio Tinto, and some way behind Vale, meaning Fortescue sits in the second half of the cost curve, at around the 75th percentile,” Mr Mills said.“This is a primary driver of our no-moat rating.”