U.S. stock markets consider opening on Wednesday

U.S. stock exchanges are looking at opening on Wednesday after monster storm Sandy receded from New York, sources said, and the New York Stock Exchange is testing a new plan to help resume trading.

U.S. stock markets were closed on Monday and Tuesday. At least some market participants believe that opening on Wednesday is critical, because many traders need prices to value their portfolios at the end of the month.

The bond markets are also closed on Tuesday, with traders aiming to reopen on Wednesday.

JPMorgan Chase & Co , the largest U.S. bank, expects many employees will be able to return to buildings starting on Wednesday, according to an internal memo obtained by Reuters.

Plans to resume trading will be complicated by the lingering effect of the storm on New York. Sandy is the worst storm to hit the city since at least 1938, and brought a record storm surge that could hobble New York's subway system for days.

If markets do open on Wednesday, there could be heavy selling, as investors whose fiscal years end in October look to get tax benefits from shedding losing stocks, said Eric Marshall, a mutual fund manager at Hodges Capital in Dallas.

If NYSE Euronext's New York Stock Exchange headquarters and trading floor are unavailable on Wednesday, trading in NYSE-listed securities will be executed on the Arca exchange, the exchange operator said in a notice issued to traders late Monday. (http://r.reuters.com/der63t)

NYSE Arca was to offer firms the ability to test the opening and closing auctions on NYSE Arca on Tuesday from 8 a.m. Eastern time (ET) (1200 GMT) until noon ET, the exchange said.

Opening auctions will run at 9:30 a.m. ET and closing auctions will run at noon, the exchange said.

"We stress that, as of now, there has been no damage to the NYSE Euronext headquarters that would impair trading floor operations," NYSE said in the notice.

The NYSE's headquarters is a few hundred yards (meters) up the street from areas of lower Manhattan that have been evacuated.

Nasdaq OMX said in a trader alert late on Monday it would operate its production system in a testing capacity from 7:30 a.m. (1130 GMT) to 12 p.m. (1600 GMT). (http://r.reuters.com/fer63t)

The NYSE had said on Sunday afternoon it planned to close its trading floor and to move all trading to its electronic market.

It backtracked on that idea after traders and regulators expressed concern about moving everything to the all-electronic venue, a plan tested on March 31 but never used live, given the difficulties and low staffing levels due to the storm.