Topeka ? One plan that Kansas’ largest electric company advanced for reducing debts and improving its financial condition isn’t going to happen.

Westar Energy Inc., headquartered in Topeka, had proposed selling its stock in ONEOK Inc., a Tulsa, Okla., natural gas company, back to ONEOK. That would have raised $738 million after taxes to pay off debt. Kansas regulators and Westar critics had embraced the idea.

But ONEOK announced Thursday it would not buy back the stock, which represents a 42.5 percent interest in the Tulsa company. It said it could build greater value for its shareholders by “preserving our financial flexibility.”

“We concluded that, at that this time and under these conditions, purchasing Westar’s shares (of ONEOK) is not in the best interest of the company and our shareholders,” said David Kyle, ONEOK’s chairman, president and chief executive officer.

In a statement issued Thursday, Westar said it was “considering what alternatives it wishes to pursue with respect to its ONEOK shares.”

ONEOK is the largest retail supplier of natural gas in Kansas, with about 635,000 customers. Westar provides electricity to about 636,000 Kansas homes and businesses.

Westar obtained its interest in ONEOK in 1997 by trading the assets of its own natural gas distribution system for ONEOK stock.

Westar had proposed to sell 44.6 million shares of ONEOK stock back to ONEOK at $21.77 per share, or a total of $971 million. Taxes would leave Westar with $233 million less to pay down its debt.

ONEOK had until next week to make a decision.

It’s unclear how much cash Westar could expect to generate to pay down debt if it attempts to sell the large block of shares on the open market.

Shares of ONEOK closed Thursday at $20.81 cents, up 5 cents on the New York Stock Exchange. Westar’s shares increased 24 cents to close at $11.85.