US open: Stocks trim gains after Yellen speech

Gains on Wall Street ebbed following a speech from the head of the US central bank in which she failed to provide any further clues as to her near-term views on monetary policy.

Similarly, she made no mention of whether stockmarkets had become too frothy, focusing instead on defending post-crisis financial regulations in the States.

Nevertheless, the lack of any direct reference to monetary policy saw the US dollar come off sharply as a result.

As of 1550 BST, the Dow Jones Industrial Average was trading higher by 0.17% or 37.88 points to 21,822.62, while the S&P 500 was rising 0.19% or 4.74 points to 2,443.66 together with a 0.19% advance on the Nasdaq Composite to 6,265.83.

"The speech offered nothing on the two big questions facing traders - the path of short term rates and the pace of balance sheet reduction. Apparently this is seen as dovish although with zero detail it's hard to really say either way. What were markets expecting? Perhaps some signal about another hike, but given there was no mention it's really a push to describe these remarks any dovish. Sometimes the market just operates on fumes, and this is probably a good case in point," said Neil Wilson, senior market analyst at ETX Capital.

"Instead of talking about the economic outlook or monetary policy she focussed on the lessons of the financial crisis and gave a thinly veiled threat to the administration that they shouldn't tinker too much with the post-crisis legislation."

On the heels of Yellen's speech the US dollar spot index was down by 0.52% at 92.79.

Meanwhile, on the economic side of things, the Department of Commerce reported that total durable goods orders in the US shrank by 6.8% month-on-month in July to reach $229.2bn, worse than economists' forecasts calling for a decline of 5.7%.

Yet the data was heavily distorted by the volatile civilian aircraft and parts category; indeed, in year-on-year terms total new orders rose by 5.0%.

In corporate news, Adamas Pharmaceuticals rocketed 44% after receiving the green light from the US Food and Drug Administration for its treatment for the involuntary movements associated with Parkinson's disease.

Estee Lauder was up by 0.3% amid reports in the British Media that Unilever may be the front-runner in the beauty contest between rival bidders for the cosmetics manufacturer.

From a sector standpoint, the strongest areas of the market were: Airlines (2.63%), Trucking (2.28%) and Gold mining (1.34%).