Upstream deal making, which has stalled with commodity prices, showed some life during May because of "opportunities too good to miss," with the most transactions still happening in North America, according to consulting firm GlobalData.

In a report Wednesday, the firm said mergers and acquisitions (M&A) accounted for half of the total upstream activity in May, with a value of $11.7 billion for 13 transactions. North America led the deal market on 35 transactions worth $12 billion, about 95% of the total.

"Of these deals, 26 were announced, with a combined value of $11.9 billion, while nine were completed, totaling $76.2 million," the firm noted.

GlobalData's Matthew Jurecky said M&A transactions are "at the highest level since December last year," excluding the Royal Dutch Shell plc and BG Group plc tie-up (see Daily GPIApril 8). Buyers "appear more aggressive to take advantage of market conditions."

Shell on Tuesday was cleared by the U.S. Federal Trade Commission to merge with BG. Closing is expected early next year.

The latest monthly upstream deals review by GlobalData found that transaction activity in May fell significantly from April because of the Shell/BG merger. Researchers analyzed M&A, equity/debt offerings, partnerships and private equity/venture capital transactions registered in the upstream segment. The data was obtained from proprietary databases, primary and secondary research, and in-house analysis.

The top deal overall in May was a joint bid by Mexico's Alfa SAB and Harbour Energy Ltd. to buy the remaining 81% stake in Colombia's Pacific Rubiales Energy for $5.3 billion. Pacific Rubiales produces about 150,000 b/d of oil, mostly in Colombia, but it wants to expand in Mexico as the energy sector opens to private investment.

The Alfa/Harbour joint bid, put together by commodity trader Noble Group Ltd. and private equity firm EIG Global Energy Partners LLC, represents the fourth largest upstream deal since oil prices plummeted last summer, GlobalData noted.

Shell/BG has been the No. 1 deal for more than a decade. Since the fall in oil prices last summer the biggest deal to follow has been Repsol SA's purchase of Canada's Talisman Energy Inc. (see Daily GPIDec. 16, 2014). No. 3 is an announced merger between LetterOne and RWE.

"If Alfa's offer proves successful, the company will have skillfully capitalized on low oil prices ravaging Pacific Rubiales' share price, which has dropped by over 70%," Jurecky noted. "Although a significant premium is being paid to the current price, rising oil prices would ultimately make the deal a bargain. Furthermore, it is a strong move strategically for more participation in Mexico, one of the top upstream markets globally in terms of opportunity."