4:30 pm : Stocks edged their way higher through the first half of the session, but they lost direction in afternoon trade. The major averages still settled with solid gains, though.

Early support was underpinned by strong gains in Europe, where participants responded positively to news that of strong demand at a Portuguese debt auction. The successful debt offering also won modest support for the euro, which finished the day with a 0.3% gain against the greenback. The British pound saw an even bigger gain of 0.7% versus the dollar.

BP Plc (BP 38.37, +1.18) released results from an internal investigation on the events leading up to the oil leak in the Gulf of Mexico. The company concluded that no single factor was responsible.

Domestic news was light, but there were reports that Goldman Sachs (GS 147.54 +2.33) is in talks with several firms about its Principal Strategies prop trading group. However, the nature of the talks may not lead Goldman Sachs to actually sell the unit. Strength in shares of GS helped drive investment bank and brokerages stocks to a 1.4% gain.

Regional banks were the strongest performers in the financial sector. The group rallied 2.5% after falling 3.9% in the prior session. Their rebound helped the financial sector tack on 1.1%, which was the biggest percentage gain of any of the major sectors in the S&P 500.

Utilities made up the only sector to settle in the red. They lost 0.5% after outperforming in the prior session.

Broad-based strength helped stocks remain strong into the close, though some afternoon volatility led the major indices to finish off of their highs with varied gains.

1:55AM Airgas: Two leading proxy advisory firms recommend that airgas stockholders vote against APD's January meeting proposal (ARG) 64.59 : Co announces that Institutional Shareholder Services and Glass Lewis recommend that ARG stockholders vote AGAINST APD's proposal to amend the Company's By-Laws to require a January 2011 meeting of stockholders. Co's board urges stockholders to Vote FOR ARG's Directors and AGAINST APD's By-Law Amendment Proposals.

1:49AM Air Products (APD) 77.79 : Co issues statement that they stand ready to negotiate with ARG Board. Co points out January annual meeting proposal is key to consummating transaction and is confident ARG shareholders will vote to retain option to maximize value of their investment. Co urges shareholders to vote FOR APD's nominees and all by-law proposals on September 15.

1:40AM BioTime CFO resigns (BTIM) 4.60 : Co announces that Steven Seinberg has resigned as CFO effective September 17, 2010. He will be returning to the practice of law at a private firm. He has agreed to assist BioTime in transition tasks on a consulting basis. Co's current SVP and COO, Robert Peabody will take on the duties of CFO on an interim basis.