When your biggest market suddenly gets more expensive to sell into, things get ugly fast. That's the situation facing Mazda Motor Corp. (MZDAY), the Hiroshima-based automaker that's watching its growth metrics crater under the weight of President Donald Trump's tariff regime.

The company makes passenger cars, trucks, and mini-vehicles, with North America representing its largest market by volume. That geographic concentration seemed fine until tariffs turned it into a liability worth billions in potential headwinds.

When Growth Scores Fall Off a Cliff

Here's where things get interesting. Mazda's Growth score plummeted from 90.49 to 50.37 within a single week after it reported fiscal second-quarter results earlier this month. For context, the Growth score measures a company's historic growth trajectory—earnings and revenue growth over short and long timeframes—then ranks it as a percentile against all other stocks.

A drop this steep typically signals one thing: a company just had a really bad quarter that's now dragging down its long-term growth profile.

The Damage Report

Mazda reported steep year-over-year declines in both sales and profits, which it directly attributes to the tariff situation. The company actually posted an operating loss during the quarter, which is never a good look.

There's a silver lining, sort of. Tariffs have been reduced ahead of a U.S. trade deal with Japan, and Mazda is hoping for a turnaround in the second half of this year. But the damage is done for now—the stock is flat year-to-date and down 4.19% over the past month following the disappointing earnings performance.

When your largest market becomes your biggest headache, even optimism about future trade deals doesn't erase the losses you've already taken.