American manufacturers of all sizes are grappling with the strongest inflationary pressure in three decades as a result of supply bottlenecks and a relentless rise in raw-materials prices in the past 13 months.

The Illinois-based manufacturer of heavy machinery said it has carried out price increases twice this year to offset higher raw material costs. Still, higher materials and freight costs, marketing and R&D spending and employee compensation are expected to hurt the company's operating profit margin in the quarter through September.

Caterpillar's shares were the biggest drag on the Dow Jones Industrial Average on Friday, having outperformed the blue chip index so far this year. The industrial giant's shares were down 4% at $203.94 in morning trade.

"Moderating margin expectations is probably not enough to drive additional near-term excitement," analysts at Jefferies wrote in a note.

The company said materials and freight costs will be higher in the second half of the year. Short-term incentive compensation is estimated to shave off $1.5 billion from company profits this year.

It did not provide an earnings forecast for this year, citing a highly fluid environment. Chief Financial Officer Andrew Bonfield told Reuters the company does not expect to offer profit per share guidance this year.

In an interview, Bonfield said the company still faces supply chain challenges and is using innovative ways such as securing supplies from non-traditional sources to deal with shortages of resin and semiconductors.

"It is a challenge, and we are dealing with it," he said.

Caterpillar is prioritizing orders that dealers have received from customers over those placed to replenish stocks at showrooms, he said. As a result, the company does not expect a significant change in dealer inventory this year, Bonfield said.

The company, an industrial bellwether and proxy for global economic activity, has been benefiting from the strongest global growth since 1976 on the back of unprecedented public spending.

A run-up in commodity prices is also encouraging miners to invest in new machines.

Caterpillar expects equipment demand to remain strong in the current quarter. Sales of construction machines in China are also expected to recover after a modest decline in the latest quarter to end the year flat.

Adjusted profit for the second quarter came in at $2.60 per share, up from $1.27 per share a year earlier. Analysts surveyed by Refinitiv, on average, expected earnings of $2.40 per share.

Equipment sales increased 31% year-on-year in the quarter to $12.2 billion, with sales rising across all regions and businesses.

(Reporting by Rajesh Kumar Singh in Chicago and Abhijith Ganapavaram in Bengaluru; Editing Louise Heavens and Steve Orlofsky)

By Rajesh Kumar Singh and Abhijith Ganapavaram