Dollar steady as Americans head to the polls

The dollar was essentially unchanged on Tuesday as Americans headed to the polls, as its moves were limited by investor caution about the U.S. midterm elections and any fallout for the world's largest economy.

The greenback has outperformed most major currencies this year, benefiting from the robust U.S. economy and rising interest rates. Investors are focused on whether congressional elections could disrupt the stellar run of the world's most liquid currency.

The Democratic Party is expected to win control of the U.S. House of Representatives, with Republicans likely to retain their majority in the Senate. A split Congress may hurt the dollar temporarily: a Democratic win in one or both chambers is likely to be seen as a repudiation of President Donald Trump and the policies which have boosted corporate growth.

That, in turn, would boost emerging market currencies hindered this year by higher U.S. rates, in particular those currencies running big external imbalances such as Turkey, Argentina and South Africa.

The dollar index was up 2 basis points on the day to 96.3 against a basket of six rivals, which could suggest the market has a slight bias for a Democratic House victory. "The market might speculate that high turnout plays more to the scenario of Democrats winning the house and Republicans winning the Senate. Otherwise this will be a quiet session until we have some more information," said Alan Ruskin, global head of currency strategy at Deutsche Bank.

But although a divided Congress may lead to a short-term downturn in the dollar, "because this outcome has the highest probability, this will limit the market impact and lead to a quick reversal of the initial reaction," said Ruskin. "Emerging market foreign exchange relief will be short-lived."

Ultimately, analysts argue it may be the case that a split Congress would be a boon for the greenback. A fully Republican Congress could mean increased trade tension and a larger deficit. If Democrats take both houses, they may roll back tax cuts and reinstate regulations that were eased by the Republicans and which have helped corporate performance.

But some analysts warn that an unexpected outcome could trigger an unwinding of long positions on the dollar which has rallied more than 7 percent from April lows against its rivals.

The euro was slightly higher at $1.1412, about 0.05 percent above this year's trough of $1.130 touched on Aug. 15.

Sterling sank after a senior member of the Northern Irish DUP party said on Tuesday it looked like Britain would leave the European Union without a divorce deal. But it had retraced its losses by mid-morning, last trading at $1.3094.