In the first quarter, operating profit at Volkswagen AG’s core brand plummeted to 73 million euros, down from 514 millions euros in the same period a year ago. Revenue for the VW unit dropped 4.6 percent while the operating margin slipped to 0.3 percent, falling short of a previous mid-term goal of 6 percent.

The declines are attributed to fewer deliveries and increased marketing costs resulting from Volkswagen’s diesel emissions scandal. First revealed in September, news that Volkswagen manipulated the results of emissions tests has forced the automaker to introduce discounts to convince car buyers to return to its dealerships.

Overall, operating profits for Volkswagen’s 12 brands increased to 3.44 billion euros from 3.33 billion euros, with revenue declining 3.4 percent to 51 billions euros. Groupwide deliveries rose 0.8 percent for the quarter to 2.5 million vehicles, allowing Volkswagen to pass global sales leader Toyota Motor Corp.