The U.S. stock market is slightly down Tuesday morning as rating agencies published concerns about Portugal and the U.K.

The S&P 500 Index is down 2.08 points, or 0.18 percent, to trade at 1,136.42 at 9:43 a.m. EST. The Dow Jones Industrial Average is down 4.08 points, or 0.04 percent, at 10,548.44.

At 11:00 am EST, Cisco (NASDAQ:CSCO) will make a significant announcement that will forever change the Internet and its impact on consumers, businesses and governments. Its shares are down 0.15 percent.

American Depository Receipts (ADRs) of European banks are among the worst performers. Those of Royal Bank of Scotland (NYSE:RBS) are down 2.46 percent and those of Allied Irish Banks (NYSE:AIB) are down 3.59 percent.

Moody's stated that the U.K. government's eventual withdraw of support from their banks may impact the debt ratings of some of those banks.

As the financial sector slowly emerges from this recent crisis, our assessment of the probability of the government providing support will revert back to a case-by-case assessment of the impact of each bank's hypothetical failure on financial stability, said the agency.

Fitch, another rating agency, was concerned that Portugal's austerity measures, announced on Monday, may not be aggressive enough.

It also said that the U.K's target of halving the deficit over four years is frankly too slow, it's a pedestrian pace of fiscal consolidation.