On Sept. 8, pipeline company Enterprise Products Partners withdrew its takeover bid for rival Williams Cos. Inc., saying that Williams' lack of engagement left it with "no actionable path forward."

Reuters reported in August that Enterprise had approached Williams earlier in the summer about a possible deal to combine the two U.S. oil and gas pipeline companies, but Williams made no official response to the approach.

"While we are disappointed, we will maintain our financial discipline as we pursue future growth opportunities for the partnership," Enterprise's CEO, Jim Teague, said in a statement.

Enterprise Product Partners' approach came after Energy Transfer Equity LP terminated its merger agreement with Williams in June after a prolonged legal battle. After that deal fell apart, nearly half of Williams' board resigned following a failed attempt to oust Williams' CEO, Alan Armstrong.