NEW YORK (CNN/Money) - If it really is a brand new day for stocks, why has the dollar been drooping?

After trading in lockstep throughout the year, the greenback and the U.S. stock market have taken diverging paths lately. While stocks over the past week have been higher, the dollar has come under pressure against the other major currencies.

"The dollar has broken two linkages," said Brown Brothers Harriman senior foreign exchange economist Anne Mills. "One of them is that after the last Gulf War the dollar went up nice and big. This Gulf War, the dollar fell like it did before the last one, but it hasn't come back. Linkage number two, the stock market has been working raggedly higher and the dollar is working it's way raggedly lower."

There are a couple of reasons being bandied about for the dollar drop -- traders selling short and reports that central banks around the world are boosting euro positions. Both fall under the category of speculation, and in the rumor-heavy currency market need to be taken with a grain of salt.

Greenback Watch Dollar dazed The next threat Buck bashing

What's worrisome is that the dollar selling doesn't make much sense within the context of a rising U.S. stock market. According to the optimists, with the war over so quickly, the economy will be loosed of its shackles and profits will rebound, ushering in a new bull market.

That's a scenario that should buck up the buck, since it would draw both business and investment to America's fair shores. Cut through the noise, and the message from the currency market is that it doesn't buy into the idea of a new bull market.

Somebody has to be wrong.

Meantime, traders on Wall Street are wondering if the stock market has reached a bridge it can't cross. Fueled by positive results from Intel and Microsoft, the market bounced higher at the open Wednesday, only to see its gains fade quickly as investors latched onto disappointing news from the likes of Coca-Cola, Altria (which many Wall Streeters doggedly persist in calling Philip Morris) and 3M.

But while there appeared good fundamental reasons for stocks' little pause, technically-minded traders also noted that the S&P 500 turned tail at around 895, the high it hit in March in that initial rally off the war. The worry is that it's a level that represents resistance -- a point where a raft of investors are hoping to sell stocks.

The worst thing about such resistance levels is that the more you pound on them without breaking through, the tougher they get, because investors who didn't get to sell the last time see them as natural places to sell on the next try.

Further stymying the bulls, after rising above Tuesday's high-point Wednesday morning, the S&P closed below Tuesday's lowpoint.

It's what traders call an outside day, and it's perceived as a negative for the market because it shows that investors came in the morning more optimistic than they were the day before, and finished the day more negative. It can mark a real shift in sentiment and often occurs at market peaks.

The upside? If stocks can battle their way past resistance levels, blowing past the sellers, it would be a sign that some deep-pocketed investors really believe that the rally has more legs to it. And stocks could go higher still.  

-- Justin Lahart is a senior writer at CNN/Money covering markets and investing.