JACKSON CENTER, Ohio — Thor Industries Inc.’s shares fell in after-hours trading Monday after the world’s largest recreational vehicle maker and a major builder of commercial buses and ambulances said it is struggling with tough competition, price discounting and uncertain economic conditions.

The company, based in Jackson Center, Ohio, reported after the market closed that it earned $31 million, or 58 cents per share, for its fiscal first quarter that ended Oct. 31. That’s up from $22.4 million, or 41 cents per share, earned in the first quarter last year.

Thor said the most recent quarter includes about $1.6 million in one-time costs for management changes and a legal settlement, which reduced its earnings per share by 2 cents

The company’s total revenue increased 30 percent to $875.6 million on stronger RV sales and a stable bus market.

Analysts polled by FactSet were expecting the company to earn 63 cents per share, adjusting for one-time items, on revenue of $876.8 million.

CEO Bob Martin said the company was pleased with its revenue growth and profitability during the first quarter, but said its results were affected by a competitive environment and the one-time expenses. He also said the intense competition has led to increased discounting that is hurting its sales and margins.

Thor will attend the largest RV tradeshow of the year this week and will assess the level of dealer confidence as it heads into the early retail show season in January.

Although the company has seen a recent upturn in demand, company chairman Peter Orthwein said that Thor remains cautious given the overall economic uncertainty and competitive pressure.

Shares fell $2.93, about 7 percent, to $40.67 in after-hours trading following the news. Its stock had gained 88 cents to close regular trading at $43.60. Tuesday it’s stock fell $5 to $38.60