NEW YORK (TheStreet) -- Energy Transfer Equity  (ETE) stock is rising by 9.26% to $9.79 on heavy trading volume on Monday afternoon, as the pipeline company's lawyers might be unable to deliver a tax opinion required for its proposed takeover of rival Williams Cos. (WMB).

The companies need a so-called "721 Opinion" from Latham & Watkins to complete their merger, and the law firm has indicated that it wouldn't be able to deliver the opinion if the deal were to close as of today, according to an SEC filing, Bloomberg reports.

Energy Transfer Equity and Williams Cos. are discussing the impact this could have on the closing of the deal.

Williams Cos. disagrees with the law firm's position, according to the filing. 

About 44.56 million shares of Energy Transfer Equity have been traded so far today, well above the company's average trading volume of roughly 19.43 shares per day. 

Separately, TheStreet Ratings team rates the stock as a "hold" with a ratings score of C.

Energy Transfer Equity's strengths such as its impressive record of earnings per share growth, compelling growth in net income and good cash flow from operations are countered by weaknesses including a generally disappointing performance in the stock itself and poor profit margins.

You can view the full analysis from the report here: ETE

TheStreet Ratings objectively rated this stock according to its "risk-adjusted" total return prospect over a 12-month investment horizon. Not based on the news in any given day, the rating may differ from Jim Cramer's view or that of this article's author.