Exxon Mobil Corp on Monday added activist investor Jeff Ubben and former finance head of Comcast Corp Michael Angelakis to its board, responding to investor pressure for changes at the top US oil producer after years of underperformance.

Exxon's shares, which have lagged closest rival Chevron Corp by a long margin in the last five years, rose 4% in premarket trading to $56.55.

Ubben, who co-founded activist hedge fund ValueAct in 2000, is allied with Exxon investor and prominent hedge fund D.E. Shaw, which has been pushing the company to cut costs and make other changes.

In January, newly formed fund Engine No. 1 launched a proxy battle for board seats, saying the company needs to do more to tackle its impact on climate change. Its campaign is supported by pension fund California State Teachers' Retirement System.

After Ubben and Angelakis' appointment, Exxon said its board now has 13 directors, 12 of whom are independent.

The appointments come after Tan Sri Wan Zulkiflee Wan Ariffin, a former chief executive officer of Malaysian state energy firm Petronas, joined Exxon's board last month.