The downgrade reflects a clear pullback in discretionary dining behavior this fall, as working-class consumers tighten budgets amid mounting economic pressures. None of this should come as a surprise, as we cautioned in our note last week, "Low-Income Consumers Pulling Back on Restaurant Spending May Signal Trouble Ahead."

Trouble ahead indeed: Shares of Chipotle cratered 18% in premarket trading, adding to a brutal 34% year-to-date decline. It's been a rotten year for investors as the burrito chain, heavily exposed to younger, cost-sensitive consumers with mounting student loans and insurmountable credit card debt, bears the brunt of an emerging pullback in discretionary spending and waning appetite for eating out.

If premarket losses hold through intraday cash, this would mark Chipotle's worst down day since July 20, 2012.

"The consumer slowdown is really affecting our business in a meaningful way," CEO Scott Boatwright told Wall Street analysts on Wednesday evening after an earnings call. 

For the third quarter, Chipotle's comparable-store sales marginally increased but missed Bloomberg Consensus expectations. There were widespread misses on key operational and margin metrics, which only suggest softer sales momentum and elevated cost pressures:

Comparable sales: +0.3% (missed Bloomberg Consensus est. +0.99%)

Adjusted EPS: $0.29 (in line with est. $0.29)

Revenue: $3.00B (slightly below est. $3.02B)

Operating margin: 15.9% (vs. est. 16.6%)

Restaurant-level margin: 24.5% (vs. est. 25.5%)

New restaurants opened: 84 (below est. 90.96)

Total restaurants at quarter-end: 3,916 (vs. est. 3,929)

Average restaurant sales: $3.13M (in line with est. $3.12M)