We could be on the verge of another major oil M&A boom like the historic one that brought Exxon and Mobil together. Mergers and acquisitions have the potential to shake up a market and send some stocks soaring, but the best industry plays aren’t all that obvious. That’s why we’ve dug deeper to find the best plays to profit from the M&A boom. 

It has been a week since one of the biggest “Merger Mondays” in recent memory.

Halliburton Company (NYSE: HAL) is buying up Baker Hughes Incorporated (NYSE: BHI) for nearly $35 billion. Then there’s Actavis PLC (NYSE: ACT) buying Allergan Inc. (NYSE: AGN) for $66 billion.

This brings the total M&A volume total for the year to over $3 trillion — more than any year since 2007. At the forefront is Goldman Sachs (NYSE: GS), which has led more deals than anyone else this year — advising on both the Halliburton-Baker Hughes and Actavis-Allergan deals.

Goldman has advised on a whopping $935 billion worth of M&A deals this year, pulling in a cool $1.7 billion for itself in the form of advisory fees. Goldman Sachs could be an underrated play on the continuation of the current M&A boom.

It trades at less than 11 times earnings and has the best return on equity all the major investment banks at 11.5%. With the stock up just 8% year-to-date, the market might be underestimating just how beneficial the M&A boom could be to its earnings.

However, I think there’s a bigger trend in M&A taking place that investors should be focusing on.  And it’s in the oil and gas space.

With the Halliburton-Baker Hughes deal, this year’s oil and gas M&A volume is nearly $370 billion, which is the highest level since this type of data was first tracked in the 1970s.

With oil prices around $75 a barrel — the lowest we’ve seen in over four years — many a companies with weak balance sheets will be forced to either merge or sell themselves to stronger players. The marrying of oil and gas companies might be the only legitimate way to weather the storm, helping lower costs and ease overcapacity issues.