Under German stock law, investors are obliged to report changes in their shareholdings in listed companies above or below certain key thresholds, such as five and 10 percent.

Rheinmetall's share capital comprises 18 million voting common shares and 18 million non-voting preference shares.

And Lombard had notified Rheinmetall that it had amassed 14.72-percent of Rheinmetall's common stock, equivalent to a stake of 7.354 percent in the overall company, the statement said.

The Mannheim-based holding company, Roechling Industrie Verwaltung GmbH, remains the biggest shareholder with an overall stake of 42.1 percent in Rheinmetall, or 73.7 percent of its voting shares and 10.5 percent of its preference shares.

Any changes in Rheinmetall's share capital are notable because the company specialises in defence technology.

The German government this year passed a new law that gave it the right to veto the acquisition by foreign investors of stakes of more than 25 percent in any companies active in the sensitive area of defence.

Press reports have suggested that US investors, such as Carlyle or General Dynamics, were interested in buying Rheinmetall, which makes tanks.