CHICAGO (Reuters) -United Airlines Holdings ( UAL ) on Wednesday forecast lower-than-expected profit in the current quarter as the industry grapples with excess seat capacity in the domestic market, which has undermined airlines' pricing power.

The Chicago-based carrier expects an adjusted profit in the range of $2.75 to $3.25 per share in the quarter through September. Analysts expected the company to report a quarterly profit of $3.44 a share, according to LSEG data.

United's shares were down about 4% in after-hours trading.

United said it expects the industry's pricing power to improve in mid-August as U.S. carriers are estimated to reduce their capacity by 300 basis points from a year ago. 

Its comments echoed those of rival Delta, which last week forecast a significant improvement in its pricing power from August onward. Like United, Delta has forecast a lower-than-expected profit for the third quarter.

Airlines are enjoying a summer travel boom, with more than 3 million people passing through U.S. airport security checkpoints on July 7, according to the Transportation Security Administration.

However, a rush among carriers to capitalize on summer travel demand has caused overcapacity, undermining their pricing power.

Major airlines have scheduled about 6% more seats in the domestic market this month than a year earlier, data from consultancy Cirium shows.

The average round-trip ticket price for a U.S. domestic flight was $543 in May, down 1% month-on-month and 3% lower from a year earlier, according to data from Airlines Reporting Corporation (ARC).

American and Southwest Airlines have cut their revenue forecasts in the second quarter, citing pressure to offer price discounts.

Analysts and industry officials say a moderation in industry capacity in the second half of the year should underpin ticket prices. Airlines have been relying on higher airfares to offset a run-up in operating costs.

United reaffirmed its 2024 profit estimate of $9-$11 a share. 

Its adjusted earnings in the June quarter came in at $4.14 a share, compared with analysts' expectations of $3.93.

The company will discuss the results on a call with analysts and investors on Thursday morning.