Although we don't believe in timing the market or panicking over daily movements, we do like to keep an eye on market changes -- just in case they're material to our investing thesis.

This morning the Dow Jones Industrial Average (^DJI -0.11%) looks slightly different than it did when it closed last Friday. The index gained three new components -- Goldman Sachs (GS -0.23%), Visa, and Nike -- and dropped Alcoa, Bank of America, and Hewlett-Packard. The change was essentially just a reshuffling of the components to make the index a better representation of the overall American economy. But today, the three newbies are putting some serious downward pressure on the index. Goldman Sachs is off by 2.5%, Visa is down 0.6%, and Nike is lower by 0.7%.

The laggard's moves have pushed the Dow down 37 points, or 0.24%, as of 12:55 p.m. EDT. However, these three stocks can't be blamed entirely for the Dow's sluggishness; the S&P 500 and NASDAQ are also moving lower, down 0.44% and 0.31%, respectively. Stocks in general are heading lower amid uncertainty about the Federal Reserve's imminent "tapering" and the debt ceiling battle in Washington.

Goldman and the other new components aren't having a bad day simply because they're new Dow components. Goldman Sachs is moving lower as the whole banking industry loses ground today. Fellow Dow component JPMorgan Chase is down 2% this afternoon following reports that Citigroup (C -0.32%) could see a massive loss of revenue because of trading activities. Citi itself is down more than 3% on the news.

All of the large multinational banks have a large amount of their business tied to trading, so when something goes wrong with a big trade, the bank could be seriously harmed. We all remember the "London Whale" incident, which JPMorgan is still cleaning up today, and while we don't yet know the little details about Citigroup, what we do know is that any and every bank is susceptible to enormous trading losses.

As for Visa and Nike, there is no news pertaining to either company's business. But because Visa is now the Dow's heaviest-weighted component -- edging out IBM by only a few dollars -- when it moves lower by a meaningful amount like today's 0.5% decline, it's likely the index as a whole will follow the large component.