* Comcast prepares all-cash bid for Fox assets
* Citigroup rises after ValueAct raises stake
* Trump to decide on Iran nuclear deal at 2 p.m. ET
* Indexes down: Dow 0.29 pct, S&P 0.33 pct, Nasdaq 0.40 pct (Updates to open)
By Medha Singh
May 8 (Reuters) - Wall Street edged lower on Tuesday, weighed down by technology and consumer discretionary stocks, while investors awaited President Donald Trump's decision on the Iran nuclear deal.
Trump will announce at 1800 GMT (2:00 p.m. ET) whether Washington will withdraw from a deal that eased economic sanctions on Iran in exchange for Tehran limiting its nuclear program.
A U.S. withdrawal would tighten economic sanctions on Iran, curtailing the country's oil output that could bolster this year's 13 percent rally in the commodity.
Crude prices were down more than half a percent - easing from 2014 highs, which had boosted Wall Street in the past two sessions.
The S&P energy index was down 0.9 percent on Tuesday, but remains a top gainer in the quarter, thanks to rising oil prices.
"(The Iran issue) has been so well covered, it's probably all in the price by now. And most recent commentary seems to be that after all the bluster, he may only partially withdraw from the deal," said Frances Hudson, global thematic strategist at Aberdeen Standard Investments.
At 9:52 a.m. EDT the Dow Jones Industrial Average was down 70.79 points, or 0.29 percent, at 24,286.53, the S&P 500 was down 8.95 points, or 0.33 percent, at 2,663.68 and the Nasdaq Composite was down 29.00 points, or 0.40 percent, at 7,236.22.
"Depending on the magnitude of energy markets being affected, it could spillover to the rest of equities in general," said Andre Bakhos, managing director at New Vines Capital LLC in Bernardsville, New Jersey.
Among stocks, Comcast fell 2.3 percent after Reuters reported the cable operator is preparing to make an all-cash offer for media assets that Twenty-First Century Fox has agreed to sell to Disney for $52 billion.
Disney, which is due to report its results after markets close, was down 0.8 percent. Fox's shares rose 1.5 percent.
The S&P consumer discretionary index was down 0.4 percent.
Citigroup advanced 2.2 percent after activist investor ValueAct invested $1.2 billion in the bank, citing its low risk and reliable revenue. The stock's gain helped the S&P financial index to be the only gainer among the major 11 indexes.
Dish Network dipped 0.1 percent after its quarterly revenue came below expectations due to a drop in its legacy pay-TV subscriptions.
Declining issues outnumbered advancers for a 1.39-to-1 ratio on the NYSE. Declining issues outnumbered advancers for a 1.11-to-1 ratio on the Nasdaq.
The S&P index recorded 8 new 52-week highs and 3 new lows, while the Nasdaq recorded 50 new highs and 21 new lows. (Reporting by Medha Singh in Bengaluru; Editing by Anil D'Silva)