Chipotle’s stock is tumbling in after-hours trading after the company reported is fourth quarter results.

The stock was down by as much as 3.2% around 4:15 p.m. ET.

It has since rebounded slightly and is lower by just 2.0% at 4:22 p.m. ET.

Chipotle missed on revenue, and same-store sales dropped by 4.8% year-over-year.

Here are the key numbers from Q4, via the Bloomberg consensus:

    EPS (adjusted): $0.55 ($0.50-$0.58 expected) Revenue: $1.03 billion ($1.04 billion expected) Same-store sales: -4.8% (-4.8% expected)

Chipotle has been struggling since the E. coli contamination scare began back in November 2015.

The stock plunged more than 50% and consumer perception of the brand fell to its lowest level since 2007, according to a survey by the YouGov Brand Index.

Moreover, Chipotle could be facing additional new obstacles. Last week, the Trump administration proposed a 20% tariff on goods from Mexico as a way to help pay for a wall along the US-Mexico border.

Although the administration has since walked it back, saying the tariff was just one option being considered, it's worth noting that this proposal could make goods from Mexico more expensive. And that could be a problem for restaurant chains like Chipotle that heavily rely on Mexican imports.