Chipotle Mexican Grill's numerous attempts to win back customers and boost sales appear to be falling flat, according to Nomura analyst Mark Kalinowski.



"The company's third-quarter promotions (including but not limited to Chiptopia) do not appear to have had the fully desired effects from the company's perspective," Kalinowski wrote in a research note Monday.



He lowered his forecasts for the company, estimating that same-store sales will be down 19.5 percent for the quarter.

Chipotle's same-store sales plunged nearly 30 percent in the first quarter, when it reported its first quarterly loss as a public company. The company swung back to profitability in the second quarter, but same-store sales declined 26.5 percent.



"We will provide a full update on our financials when we release our third-quarter earnings on Oct. 25," Chris Arnold, a spokesman for Chipotle, told CNBC.



Last week, StreetAccount noted that a report by M Science said traffic remains weak for the burrito chain.

Chipotle shares, which are down more than 45 percent over the past year, were trading lower Monday. At midday, shares were exchanged hands at $396.96, down $7.19, or 1.8 percent.

The company has been working hard to win back customers of all ages with promotions, freebies and a temporary loyalty program. A whopping 85,000 people are slated to receive free catering from Chipotle for successfully completing the burrito chain's Chiptopia loyalty program, Arnold told CNBC earlier this month.

In addition, the company announced last week that it will once again offer $3 burritos, bowls, salads and tacos on Halloween to customers who arrive at stores in costumes. The promotion is another move by the burrito chain to bolster foot traffic.