Sixty-six institutional investors are to take legal action against Volkswagen in its German home market after the carmaker cheated emissions tests in the United States. The first claim will be made within the next seven days.

The legal action will heap further pressure on Volkswagen, which earlier this month said its annual sales fell last year for the first time in more than a decade. Klaus Nieding, a lawyer at Nieding and Barth, the German law firm, said a capital market model claim, which is similar to a collective lawsuit in the US, will be filed “within the next week” in Germany on behalf of a US institutional investor that has suffered a “big loss”. He declined to name the plaintiff.

The other 65 institutional investors are expected to join that claim.

Nieding and Barth is working with MüllerSeidelVos, a fellow German firm, and Robbins Geller Rudman and Dowd, a US law firm, to represent investors that have contacted DSW, a German shareholder protection association. Mr Nieding said the law firms collectively represent “many foreign institutional investors, primarily from the US, with claims of several hundred million euros”.

He added: “We are representing, as far as we know, the largest number of claims and of shareholders [in Germany].”

Bentham Europe, a litigation finance group backed by Elliott Management, the US hedge fund, and Australian-listed IMF Bentham, is also expected to file a damages claim in Germany.

Volkswagen is facing additional legal action outside its home market. Class actions against the carmaker, which allow one person to sue on behalf of a group of individuals or companies, have already been filed in the US and Australia.

The US justice department, on behalf of the EPA, has also filed a lawsuit against Volkswagen, while several institutional investors are still weighing up whether to take legal action against VW.

– Copyright The Financial Times Limited 2016