* Bilfinger warned on 2017 profit late on Tuesday
* CEO says believes now through with reassessing legacy projects
* Shares fall as much as 5 pct (Releads with shares, adds trader comment, details on U.S. legacy projects)
FRANKFURT, July 12 (Reuters) - Shares in German engineering services firm Bilfinger fell as much as 4 percent on Wednesday after the company issued its first profit warning since Tom Blades became chief executive a year ago.
Blades has been trying to steer the company into calmer waters after it endured six profit warnings and four CEOs in the space of two years amid a decline in the company's primary energy markets.
Late on Tuesday Bilfinger abandoned its target to improve its operating profitability this year after it made provisions of 55 million euros ($63 million) for projects taken on by its U.S. subsidiary Westcon in 2015 and 2016. They were approved just before Blades took over in July 2016.
Blades said he believed Bilfinger was now through with reassessing the risks from old projects, although it could not be ruled out that fresh issues would arise.
Bilfinger shares were down 2.34 percent at 33.58 euros by 0716 GMT, at the bottom of the German mid-cap index, having fallen to 33 euros in early trading.
"Another setback!" a Frankfurt-based trader said in a note. "Restructuring will obviously take some time."
Blades, together with a new finance chief, has instituted new risk-management processes.
He said the fresh provisions were for downstream petrochemicals projects that Westcon had embarked on in the southern United States after the oil price started falling.
Bilfinger, once a storied name in German construction that was associated with the Munich Olympic stadium among other projects, lost out in a bet to focus on higher-margin services in the early years of this decade.
Its main customers were energy utilities and petrochemical companies, which suffered badly and cut spending as the oil price went into decline. ($1 = 0.8709 euros) (Reporting by Georgina Prodhan; Editing by Edward Taylor and Susan Fenton)