RIYADH/DUBAI (Reuters) - U.S. President Donald Trump announced deals worth hundreds of billions of dollars between the United States and Gulf nations during his four-day tour of the oil- and gas-rich Middle East.

The agreements span sectors including aviation, artificial intelligence, infrastructure, financial markets and energy.

Here is an overview of major deals and announcements during the tour:

* The White House said Abu Dhabi's Etihad Airways had committed to spend $14.5 billion to buy 28 Boeing 787 and 777X aircraft powered by GE Aerospace engines.

* ExxonMobil, Occidental Petroleum, and EOG Resources have committed to invest $60 billion in energy production in the UAE, said Sultan Al Jaber, Abu Dhabi oil giant ADNOC's chief executive.

* U.S.-based Holtec International and Abu Dhabi's IHC Industrial Holding Company are entering cooperation to build a fleet of Holtec's SMR-300 small modular reactors, starting at the Palisades site in Michigan.

This agreement includes a commitment from IHC to spend up to $30 billion, according to the White House.

* The White House said Emirates Global Aluminium will build a primary aluminium smelter worth $4 billion in Oklahoma.

* Saudi Aramco has signed 34 agreements with major U.S. companies, potentially worth as much as $90 billion, the oil giant said.

* Qatar Airways signed a deal to purchase jets from U.S. manufacturer Boeing.

* Nvidia said it will sell hundreds of thousands of AI chips in Saudi Arabia, with a first tranche of 18,000 of its newest "Blackwell" chips going to Humain, an AI startup the kingdom's sovereign wealth fund launched this week.

* Qualcomm Inc said it signed a memo of understanding to develop and build a data centre central processor.

* Franklin Templeton said it has signed a non-binding memorandum of understanding with Saudi Arabia's Public Investment Fund to partner in investing up to $5 billion in the kingdom's financial markets.

* The White House said U.S. engineering firm Parsons had won 30 projects worth up to $97 billion from Qatar.

* Neuberger Berman signed an agreement with PIF to invest up to $6 billion in the kingdom, and to launch a Riyadh-based multi-asset investment management platform.

* BlackRock Saudi Arabia and PIF signed a non-binding letter of intent at the Saudi-U.S. Investment Forum to formalise their strategic collaboration through potential new allocations to the BlackRock Riyadh Investment Management platform.

* Cisco said it will collaborate with the AI Infrastructure Partnership, which is led by BlackRock, Global Infrastructure Partners, MGX, Microsoft, Nvidia and xAI.

The company also said it will join Saudi Arabia's Humain and extend its strategic partnership with Abu Dhabi's G42 to advance AI innovation and infrastructure development.

* Infrastructure investment manager I Squared Capital said it has signed a memorandum of understanding with PIF to establish a dedicated infrastructure investment strategy focused on the Middle East.

* Amazon Web Services and Saudi Arabia's AI startup Humain said they planned to invest $5 billion-plus in a strategic partnership to build an "AI Zone" in the kingdom.

* U.S. chip firm AMD and Humain said they would build AI infrastructure that will lead them to invest up to $10 billion to deploy 500 megawatts of AI computing capacity over the next five years.

* Saudi Arabian DataVolt plans to invest $20 billion in AI data centres and energy infrastructure in the United States.

* Google , DataVolt, Oracle, Salesforce, AMD, and Uber say they will invest $80 billion in technologies in both countries.

* Construction consulting firms Hill International, Jacobs, Parsons, and AECOM are building infrastructure projects such as King Salman International Airport, King Salman Park, The Vault, Qiddiya City, and more, totalling $2 billion in U.S. services exports.

* Additional major exports include GE Vernova's gas turbines and energy solutions totalling $14.2 billion and Boeing 737-8 passenger aircraft for AviLease totalling $4.8 billion.

* Healthcare firm Shamekh IV Solutions will be investing $5.8 billion, including a plant in Michigan to launch a high-capacity IV fluid facility.

* Hassana Investment Company and Franklin Templeton signed a memorandum of understanding valued at $150 million to explore a strategic partnership related to investments in Saudi private credit opportunities.

* Saudi Aramco said it would sign memorandums of understanding with U.S. liquefied natural gas producer NextDecade and utility Sempra.

* U.S.-based investment platform Burkhan World Investments said it signed memorandums of understanding with Saudi partners, totalling $15 billion in investment commitments.