Fisher & Paykel Healthcare Corp Ltd (ASX: FPH) shares are falling on Thursday morning.

At the time of writing, the ASX 100 stock is down almost 5% to $32.97.

This follows the release of the medical device company's half year results.

ASX 100 stock falls on results day

• Operating revenue up 18% to a record of NZ$951.2 million
• Gross margin improved to 61.9%
• Net profit after tax up 43% to NZ$153.2 million
• Interim dividend up 3% to 18.5 NZ cents per share
• Investment in R&D was 12% of revenue or NZ$110.1 million

What happened during the half?

For the six months ended 30 September, Fisher & Paykel Healthcare reported an 18% increase in operating revenue to a record of NZ$951.2 million.

This was driven by strong top line growth from both its Hospital and Homecare segments.

Hospital operating revenue, which includes humidification products used in respiratory, acute and surgical care, increased 21% to approximately NZ$591.4 million for the half. Hospital new applications consumables revenue increased 24% in constant currency.

Whereas Homecare operating revenue increased 14% to approximately NZ$359.4 million. Sales of masks and accessories for treating obstructive sleep apnea (OSA) were up 14% in constant currency.

The ASX 100 stock's gross margin improved markedly during the half to 61.9%. This represents a 141 basis-point increase in reported currency over the prior comparable period or a 198 basis-point increase in constant currency.

This ultimately led to Fisher & Paykel Healthcare posting a 43% increase in net profit after tax to NZ$153.2 million for the half.

Commenting on the half, the company's CEO, Lewis Gradon, said:

This result was driven primarily by new product introductions and changing clinical practice. Early indications are that a relatively high hospital census during the period may have contributed as well, as hospitals returned to more normalised staffing and capacity, and seasonal hospitalisations in the Northern Hemisphere from FY24 persisted into the beginning of our current financial year.

Growth has been broad-based across our entire portfolio of hospital products, including in invasive and noninvasive ventilation and Optiflow for respiratory and anesthesia patients, all suggesting that we are making headway with changing clinical practice. We are also pleased with the continued strong performance of our range of masks for patients with obstructive sleep apnea.

Outlook

Despite the strong half, the ASX 100 stock has only held firm with its guidance for the full year.

It has reiterated its guidance for revenue of NZ$1.9 billion to NZ$2 billion and net profit after tax of approximately NZ$320 million to NZ$370 million.

It seems that the market was hoping that the company would increase its guidance this morning.