Fiat Group Automobiles saw its year-on-year sales in Europe plummet 13.3% last month causing its market share to drop from 9.2% in February to 7.4%.
Fiat group sales for the first quarter of 2008 fell 5.1% over the same period last year.
With a market share last month of 7.4%, compared to 7.6% in March 2007, Fiat fell into sixth place from fourth in February.
For the first three months of the year, Fiat had an average market share of 8.4% compared to 8.6% in the first quarter of 2007.
Following a 8.7% year-on-year jump in February, overall new car sales in Europe in March sank 9.5%, while sales in Italy sank 18.8% over March 2007.
For the first three months of the year, new car sales in Europe were off 1.7%, over the first quarter of 2007, while in Italy they were down 10%.
Fiat Group Automobiles include the Fiat marque as well as Lancia and Alfa Romeo.