US STOCKS-S&P, Dow little changed, Apple props up Nasdaq
* Fed's John Williams sees 2-3 rate hikes in 2016
* Yellen to speak later in the week
* Monsanto jumps after Bayer's $62 bln buyout offer
* Indexes: Dow up 0.07 pct, S&P down 0.05 pct, Nasdaq up 0.15 pct (Updates to early afternoon)
By Tanya Agrawal
May 23 (Reuters) - The S&P 500 and Dow trimmed gains and were little changed in early afternoon trading on Monday, while a bounce in Apple's stock kept the Nasdaq in positive territory.
The benchmark Philadelphia SE Semiconductors Index was up 1 percent, following a 3.2 percent rise on Friday, after a report that the iPhone maker had asked its suppliers to prepare 72-78 million units, above the market's expectation of 65 million units.
Apple's shares rose 1.44 percent to $96.58.
However, oil slid as Iran vowed to ramp up output and rig reductions paused in the United States, pulling down oil major Exxon by 0.6 percent. Continuación...