Brooke Sutherland is a Bloomberg Gadfly columnist covering deals. She previously wrote an M&A column for Bloomberg News.

Tara Lachapelle is a Bloomberg Gadfly columnist covering deals. She previously wrote an M&A column for Bloomberg News.

For mergers and acquisitions, it's been a year of superlatives. But how many are left?

Pfizer and Allergan on Monday announced a record-sized $160 billion combination, adding to record consolidation in the drug and health-care industries. And elsewhere? Let's see, there's record dealmaking among chipmakers, a record tech acquisition, records in both food and beer. All that adds up to a record year for takeovers worldwide.

Record, record, record. Financial journalists have grown tired of the word. Bankers love it.  

Major Deals of 2015
Companies in almost every industry struck deals that were at or near records.
Source: Bloomberg
Transaction values include most recently reported net debt. Stock deals use acquirers' 20-day average price.

What's driving all this activity? In many cases, companies are resorting to acquisitions because they've run out of other ways to grow. Cheap financing stemming from the Fed's zero-interest-rate policy has also helped. The question is whether the bonanza will extend into 2016.

The simple answer is yes. There are some fairly large acquisitions left in industries such as pharmaceuticals, industrials and energy. But don't expect the same degree of activity as this year. For one, borrowing costs may rise, with U.S. central bankers poised to lift benchmark rates for the first time in years. And now that so many massive mergers have been struck, there are simply very few big companies left to consolidate. Or at least, very few that can pass regulatory muster going forward. 

Up, Up and Away
Deal activity has now surpassed the highs of the M&A boom years last decade.
Source: Bloomberg

Take health insurance. Managed-care providers struck three multi-billion-dollar deals in a matter of weeks, the biggest of which were Anthem's $50 billion takeover of Cigna and Aetna's roughly $30 billion offer for Humana (all figures include net debt). With criticism mounting from doctor and hospital groups, it's going to be hard enough getting antitrust approval for those two takeovers, let alone a bigger deal down the road -- so count out a UnitedHealth bid for a combined Aetna-Humana or Anthem-Cigna.

AB InBev's $120 billion merger with SABMiller leaves only Carlsberg and Heineken as big beer targets. Heineken, valued at $52 billion, has been clear that it wants to remain independent, though. These companies are more likely to continue buying increasingly popular microbreweries, or brands such as Guinness, than to pursue more mega-mergers. 

The list of possible hotel big deals is getting shorter, too, now that Marriott has emerged as Starwood's acquirer. In the drug-store space, Walgreens' takeover of Rite Aid will shrink the industry down to just two major providers: Walgreens and CVS, plus a host of tinier pharmacies. 

Prospects for mega-sized purchases are similarly slim in telecom, if Time Warner Cable, twice at the heart of one of the biggest cable-TV purchases ever, is any guide. In April, Comcast's plan to buy the company collapsed after regulators firmly objected to the merger. One month later, Charter stepped in with a bid for Time Warner Cable that is still awaiting approval. AT&T closed on its acquisition of DirecTV in July, and France's Altice agreed to buy Cablevision in September.

That's not to say bigger deals are dead. Even as authorities take a harder look at communications consolidation, there may be one or two left. Maybe. Comcast will face scrutiny no matter what, just given its size. But there has been speculation that it could buy T-Mobile to offer wireless services. There's also Dish Network, run by the never-deal-shy Charlie Ergen, who in the past bid (unsuccessfully) for Sprint and Clearwire and held talks about purchasing T-Mobile earlier this year. Patrick Drahi's Altice could do more U.S. takeovers as well. 

The year's biggest industrial and chemicals deals are still incomplete. Canadian Pacific just launched a more than $35 billion bid for Norfolk Southern. It remains to be seen if the Canadian railroad can get its U.S. peer -- and regulators -- on board with the plan. Meanwhile, Syngenta, the world's biggest pesticide maker, is in play again after rebuffing Monsanto earlier this year. China National Chemical has made an offer, while Monsanto is weighing another pursuit. At minimum, that's a $40 billion-plus purchase that likely gets done one way or the other.

And that's not counting whatever GE decides to do with the billions it's making on the wind-down of GE Capital. 

Energy and semiconductors are other areas where perhaps M&A volumes have further to rise. Besides Shell's massive $79 billion purchase of BG and Apache's rejection of Anadarko, there hasn't been the flurry of oil and gas deals that were predicted at the start of the year. With crude prices still in a rout, more transactions should occur. And while semiconductor deals are far and away at a record already, there are a handful of chipmakers that have yet to take part in the activity -- like Texas Instruments -- and will probably feel pressure to do so.

Back to pharma: Mylan is on the hunt for a new target after Perrigo shareholders rebuffed its roughly $30 billion takeover offer. Sanford C. Bernstein suggests Sanofi's generic drug business, or Pfizer's, which could become available in a few years after the Allergan purchase is digested. Perrigo wants to make purchases of its own, with $13.6 billion Endo as one possibility. Let's not forget Shire's pursuit of $23 billion Baxalta or Amgen's reported plans for a $10 billion deal.

So bankers will be busy, but their biggest M&A milestones are likely behind them. 

This column does not necessarily reflect the opinion of Bloomberg LP and its owners.

To contact the authors of this story:
Brooke Sutherland in New York at bsutherland7@bloomberg.net
Tara Lachapelle in New York at tlachapelle@bloomberg.net

To contact the editor responsible for this story:
Beth Williams at bewilliams@bloomberg.net