Shares in Scott Wilson soared on the possibility of a bidding war between two US firms for the design and engineering consultancy.First thing this morning, engineering group URS unveiled an agreed cash offer worth £161m, 210p per share, only to be swiftly followed by a statement from another US firm, Colorado-based CH2M Hill, that it too is looking at making an offer for Scott.Both companies are huge relative to Scott Wilson. URS' revenues last year were more than $9bn and CH2M Hill over $6bn, but both see major synergies through the integration of the UK firm's network."Outside of the UK, Scott Wilson's offices in Warsaw, Hong Kong, New Delhi and Dubai provide a strong complement to URS's locations in Frankfurt, Paris, Madrid, Milan, Shanghai, Sydney and Toronto, further expanding our geographic footprint and ability to support public and private sector clients worldwide," URS chief executive Martin Koffel said.Employee-owned CH2M Hill added it has undertaken due diligence on Scott Wilson and is considering its position with respect to making a cash offer.For the year to end-April, Scott's sales fell to £340m from £360m and operating profits rose to £23.9m from £22.6m. Pre-tax profits were £18m against £9.4m.