The Bundeskartellamt has approved the acquisition of the Stumpp Group by Strabag AG subject to a condition precedent requiring the divestiture of a key production asset. Under the decision published on 2 March 2026, clearance is conditional upon the sale of Stumpp’s rolled asphalt mixing plant in Zimmern to a suitable independent purchaser prior to completion of the transaction.
The transaction concerns the acquisition of all shares in the Stumpp Group, headquartered in Balingen and active in road construction in southern Baden-Württemberg. Stumpp operates two rolled asphalt mixing plants in Zimmern and Balingen and also holds interests in quarries. Strabag, one of Europe’s largest construction groups, maintains a dense network of rolled asphalt mixing plants across Germany and holds quarry participations in the region concerned. Although Strabag has not previously been among the leading road construction providers within Stumpp’s specific area of activity, it already operates several mixing plants in the relevant region.
According to Andreas Mundt, President of the Bundeskartellamt, the full takeover of Stumpp, including its two mixing plants, would have significantly strengthened Strabag’s position in the area between Stuttgart and Lake Constance. The authority found that, absent remedies, nearly half of the rolled asphalt marketed in the region would have been attributable to a single company. Such a concentration would have elevated Strabag well beyond the statutory presumption of market dominance at a 40 percent market share threshold.
Rolled asphalt constitutes a central input for road construction. It is produced in specialized mixing plants and, due to its technical characteristics, must typically be laid within a short period following production. As a result, transport distances are both technically and economically constrained, leading to geographically narrow, regional markets. In this case, the authority defined the relevant geographic market as the region between Stuttgart and Lake Constance. Within this area, four mixing plants operated by Strabag and Stumpp are strategically located along major transport routes and complement each other in a manner that would have significantly enhanced the merged entity’s market coverage.
The competitive concerns extended beyond the market for rolled asphalt itself. The Bundeskartellamt also identified potential effects on the upstream market for crushed natural stone and, more notably, on the downstream regional market for road construction services. Remaining competitors in the relevant area are predominantly medium-sized enterprises with considerably lower financial strength, each holding market shares below 15 percent.
To address these concerns, the parties offered to divest the rolled asphalt mixing plant in Zimmern before closing. The Bundeskartellamt subjected this proposal to a comprehensive market test, consulting other market participants in the region. Following its examination, the authority concluded that the divestiture is, in principle, capable of preventing the emergence of a dominant position in the regional rolled asphalt market. Without the Zimmern facility, Strabag’s market share would remain well below the statutory presumption threshold. However, the effectiveness of the remedy depends on identifying a suitable independent purchaser capable of ensuring the long-term viability of the Zimmern plant.
The decision of the Bundeskartellamt has not yet become final. An appeal may be lodged, in which case jurisdiction would lie with the Oberlandesgericht Düsseldorf.