Sept 21 (Reuters) - Magellan Midstream Partners' (MMP.N) unitholders on Thursday voted in favour of its sale to larger rival ONEOK Inc (OKE.N) for $18.8 billion, creating one of the largest U.S. energy pipeline companies.

The sale had come under scrutiny with one of the top holders in Magellan, Energy Income Partners LLC, saying in June that it would vote against the deal, due to a burdensome tax structure.

Independent proxy advisory firms Glass Lewis & Co and ISS had recommended a vote in favor of the sale.

According to preliminary results, about 96% of the votes cast were in favor of the transaction.

Unitholders, however, voted against compensation to be paid to executive officers related to the deal.

Magellan, in its proxy, cautions that the merger is not conditioned on the compensation vote and that if the acquisition is approved, the executive compensation is payable.

Chief Executive Aaron Milford would receive about $28 million in cash, stock and benefits after the merger while Chief Financial Officer Jeff Holman would get about $15 million, the proxy showed.

Michael Mears, Magellan's previous chief executive officer, also would receive about $26.5 million in equity, while the company's current chief commercial officer and general council will receive multi-million dollar packages.

Magellan, however, said it expects ONEOK to consider the outcome of the compensation vote, along with other factors, when considering future executive pay.

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