The S&P/ASX 200 Index (ASX: XJO) is on course to end the week with a small gain. At the time of writing, the benchmark index is up 0.3% to 7,992.8 points.

Four ASX shares that have failed to follow the market higher today are listed below. Here's why they are falling:

Block Inc (ASX: XYZ)

The Block share price is down a further 3.5% to $90.80. This follows another pullback in the payments giant's NYSE listed shares overnight. This latest decline means that the Afterpay owner's shares have now dropped 40% from their 52-week high and trade within touching distance of a 52-week low.

Corporate Travel Management Ltd (ASX: CTD)

The Corporate Travel Management share price is down almost 3% to $14.56. Investors have been selling the corporate travel specialist's shares after it announced the exit of its ANZ CEO. The company advised that Greg McCarthy will step down on 30 June and be succeeded by former AMEX GBT General Manager and Regional Vice President APAC, Jo Sully. No explanation has been given for the exit, but founder and managing director, Jamie Pherous, spoke positively about the outgoing executive. He said: "I want to thank Greg for his unwavering commitment to CTM's clients, employees and industry partners over the past 7 years. His leadership has enabled the business to navigate periods of significant disruption and change, and come out stronger, more connected, and more valued than ever before."

Incitec Pivot Ltd (ASX: IPL)

The Incitec Pivot share price is down over 2% to $2.62. Investors have been selling this agricultural chemicals company's shares following the release of a business update. Incitec Pivot warned that the key Dyno Nobel business has been negatively impacted by heavy rainfall in Queensland. In addition, the company's Fertilisers segment has been hit hard by dry conditions in South Australia, Victoria, and southern NSW. Together with cyclonic activity in Queensland and northern NSW, it only expects 10% of its fertiliser earnings to fall in the first half, with the balance pushed into the second half.

Pro Medicus Limited (ASX: PME)

The Pro Medicus share price is down a further 2.5% to $205.15. Investors have been selling this health imaging technology company's shares this week after brokers downgraded their earnings estimates to reflect the timing of new contract installations. One of those was Bell Potter, which remains positive but concedes that "due to these exceptionally high levels of new work and potential for delays on installations, there is more scope than at any time in the recent past for share price volatility upon the announcement of earnings." Nevertheless, Bell Potter has retained its buy rating with a reduced price target of $280.00 (from $330.00).