Dec 14 (Reuters) - Six U.S. oil and gas bankers who missed out on a wave of mega deals in the oil patch after leaving mergers and acquisitions powerhouse Citigroup last year to join smaller firm Guggenheim Securities are now decamping to Moelis & Co, according to people familiar with the matter.

The merry-go-round underscores the restlessness of dealmakers who try to get hired on big, high-prestige deals while working for firms that let them keep more of the advisory fees they generate. Energy and power has been the most active sector for dealmaking this year, accounting for $460.3 billion worth of transactions globally, up 4% year-on-year, according to LSEG.

The six bankers which Moelis has hired from Guggenheim include Muhammad Laghari, Alexander Burpee, Benjamin Dubois, and Ryan Staha, said the sources, who requested anonymity because the moves have not yet been announced.

The bankers, who previously worked at Citigroup together, are on gardening leave and will start at Moelis in the next few weeks, the sources added.

Moelis and Guggenheim declined to comment.

Dealmaking has soared among oil and gas producers in the last two months, as companies seek to boost profitability by adding more and better acreage. Exxon Mobil clinched a $60 billion deal to buy Pioneer Natural Resources and Chevron announced a $53 billion agreement to buy Hess . Occidental Petroleum said on Monday it would buy closely held U.S. shale oil producer CrownRock for $12 billion including debt.

While Citigroup advised Pioneer on its sale to Exxon, neither Guggenheim nor Moelis were on these deals.

Deal-focused investment banking boutiques like Moelis and Guggenheim typically allow their bankers to keep more of their client fees compared with big bulge-bracket banks like Citigroup, which run more diverse businesses they have to pay for.

Guggenheim ranks 19th in LSEG's league table for U.S. oil and gas deals this year with $5.8 billion of announced transactions, having been outside the top 25 advisers in 2022. Its largest mandate was helping Civitas Resources on its $4.7 billion purchase of energy producers from private equity firm NGP, which was announced in June.

Moelis has also been a minor U.S. player. It is currently 25th in the same league table this year, and was outside the top 25 in 2022. It has close ties, however, to a number of major international energy clients, including Saudi Aramco and Abu Dhabi National Oil Co. (Reporting by David French in New York Editing by Matthew Lewis)