The title of the top IT company in the world can vary depending on the criteria used for evaluation, such as revenue, market capitalization, innovation, brand value, or influence on the tech industry. As of my last update, companies like Apple, Microsoft, Amazon, and Alphabet (Google's parent company) are often at the top of such lists.

Apple Inc. is frequently recognized as the top IT company due to its massive market capitalization, which has often exceeded $2 trillion, making it one of the most valuable companies in the world. Apple's success is driven by its popular consumer electronics, such as the iPhone, iPad, and Mac computers, as well as its services like the App Store, iCloud, and Apple Music.

Microsoft Corporation is another contender for the top spot, with a strong presence in both consumer and enterprise markets. Microsoft's Windows operating system is ubiquitous in personal computing, and its Office suite of productivity software is a standard in many businesses. Additionally, Microsoft has made significant strides in cloud computing with its Azure platform.

Amazon.com, Inc. is a dominant force in e-commerce and cloud computing through its Amazon Web Services (AWS) division. AWS is a leader in the cloud infrastructure market, providing services to a vast array of businesses and governments.

Alphabet Inc., the parent company of Google, is a leader in online advertising, search engine technology, and has a growing presence in hardware, software, and other tech ventures, including autonomous vehicles through its subsidiary Waymo.

It's important to note that the rankings can change from year to year based on financial performance, market trends, and technological advancements. For the most current information, it's best to refer to the latest financial reports, market analyses, and industry rankings from reputable sources such as Forbes, Fortune, or Bloomberg.