GCC-listed companies reported record profits of $67.9 billion in the first quarter, according to a report by Kamco Invest.

Your sentence is already correct and clear. If you want slightly refined versions depending on style, here are options:

1. Standard news style (slightly smoother):
GCC-listed companies reported record first-quarter profits of $67.9 billion, according to a report by Kamco Invest.

2. More formal:
Companies listed across the Gulf Cooperation Council (GCC) recorded record profits of $67.9 billion in the first quarter, according to Kamco Invest.

3. More concise headline style:
GCC-listed firms post record $67.9 billion Q1 profits, Kamco Invest reports.