Renault will book a one-off loss of about 9.5 billion euros ($11 billion) on its stake in Nissan Motor, the French carmaker said on Tuesday, writing down its years-long investment in its Japanese partner that is battling slumping sales.

Renault SA will recognize an estimated €9.5 billion ($11.2 billion) non-cash loss after changing the way it accounts for its stake in ailing Japanese carmaker Nissan Motor Co.

Renault reported an $11 billion non-cash loss on its 35.7% Nissan stake, shifting to a share price-based accounting method. Nissan's weak sales, outdated lineup, and $4.5 billion loss highlight the strained alliance.