Louisiana regulators Wednesday rejected a $4.9 billion bid by international investors to buy Cleco.

Based in Pineville, Cleco Power LLC sells electricity to about 286,000 customers on the North Shore, in Acadiana and throughout central Louisiana.

The vote by the five elected members of the Louisiana Public Service Commission effectively kills the transaction that had been negotiated largely behind closed doors for the past 17 months.

Cleco’s stock price fell $2.44 to $47.15 per share in the 15 minutes after the vote and plummeted to $45.22 within an hour of the vote. The stock cost about $46 a share when the transaction was announced in 2014.

The deal would have been good for Cleco shareholders, who would have sold their stock at a 15 percent premium — about $55.37 per share — to a consortium of investors led by Macquarie Infrastructure and Real Assets, based in Sydney, Australia.

But a majority of the PSC regulators, led by Chairman Clyde Holloway, R-Forest Hill, argued the transaction endangered the monthly rates Cleco customers pay for their power.

“I do not like the tax scheme. … If there ever was an issue you don’t want the public to hear, it is this issue,” said Holloway, whose district includes the most Cleco customers, about 750 of whom had called his office to complain about the deal during the past week.

Cleco President Darren Olagues testified that other utilities benefit from the tax break that some of the commissioners faulted. He said the PSC should not take different approaches to tax policy for different utilities.

Under the deal, the new owners of the 80-year-old Cleco Power LLC would have been able to pocket taxes collected as part of the monthly rates, rather than turning the proceeds over to state and federal authorities.

Holloway also didn’t like that the locally owned company would be bought by Australian and Canadian investors who planned to sell the utility in eight to 10 years. Additionally, the “double leverage” method of financing the $4.85 billion transaction — allowing the buyers to use borrowed money to borrow more money — left open the possibility that Cleco customers could be held responsible for the debt.

New Orleans Commissioner Lambert Boissiere III, a Democrat, said voting for the deal would mean the new owners could immediately take advantage of the tax breaks and could borrow money. Any of the promised fixes to these issues are months away and not guaranteed, he said.

“The minute we vote, the ratepayers are at risk,” Boissiere said. “I don’t know that I’m here to make sure Macquarie gets a good deal.”

Boissiere and fellow Democrat Foster Campbell, of Bossier Parish, joined Holloway, a Republican, opposing a procedural vote aimed at delaying a decision. After that vote failed, Republican Commissioners Scott Angelle, of Breaux Bridge, and Eric Skrmetta, of Metairie, raised no objection to rejecting the deal.

Andrew M. Chapman, the managing director of Macquarie Infrastructure Management (USA) Inc., complained that he was given only about 30 minutes to speak during a seven-hour hearing that featured opponent after opponent criticizing the sale. Holloway, however, cut off debate and demanded an immediate vote when Campbell said he had to leave.

Neither Chapman nor Olagues would answer questions after the vote.

But Cleco released a statement expressing its disappointment.

“We will review our options and make a decision and communicate that decision at the appropriate time,” said Robbyn Cooper, a corporate spokeswoman.

State law allows parties aggrieved by a commission vote to appeal the decision to 19th Judicial District Court in Baton Rouge. The state constitution requires the commission oversee many of the business decisions made by the privately owned companies because the utilities operate as monopolies in their service territories and are allowed to include a profit — generally about 10 percent — in the rates they charge.

Chapman asked the regulators to look closely at the trend of locally owned utilities being bought up by big conglomerates. Employees are laid off as jobs are consolidated.

In previous purchases of American utility companies, the Macquarie partners have kept the management local and didn’t lay off employees, he said. The investors are using money from pension funds and thus are seeking stable investments.

The newly owned Cleco would have included four Louisiana residents, three of whom also are customers, on the board of directors. Only one of Cleco’s present directors lives in Louisiana.

Skrmetta, who represents the north shore of Lake Pontchartrain, the second-largest pool of Cleco customers, pointed out that ratepayers weren’t asked to pay for the transaction. In fact, had the transaction taken place, rates would have been lowered — both from a $125 million cash credit the buyers would have given Cleco customers and from additional efficiencies.

Holloway said $125 million sounds like a lot of money, but it would have been spread over 15 years. That means the typical residential customer using 1,250 kilowatt hour of electricity would have seen only a $1.58 decrease in their monthly bill.

“It is $8.3 million a year that we didn’t have the wherewithal to beat out of Cleco before,” said Angelle, who also is a Cleco customer.

Angelle said nothing else is available that would immediately lower Cleco’s rates, which are the highest in the state.

“There is no question that this transaction brings harm to the ratepayers,” said Casey DeMoss, the head of the New Orleans-based consumer group, Alliance for Affordable Energy. The 77 concessions agreed to by the Macquarie, along with the $125 million credit, are efforts to mitigate what the experts say are possible problems for customers.

DeMoss said the potential exists that when the loan’s balloon payments come due, the economic situation could be different, credit could be harder to get and more expensive, leaving customers having to pay more on their monthly bills.

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