Stocks end up slightly as investors await Fed decision on rates tomorrow

Stocks moved slightly higher Tuesday ahead of Wednesday's interest rate decision from the Federal Reserve.

The Nasdaq rose 0.1%, while the Dow Jones industrial average and the S&P 500 climbed by lesser amounts, the broad S&P 500 ending just fractionally positive.

With the Fed's two-day meeting underway, Wall Street's focus is on the Fed and its chairperson Janet Yellen. The question is whether the U.S. central bank, which has held off on interest rate increases this year, will stand pat again or surprise markets and increase borrowing costs. Low interest rates from the Fed are designed to boost growth, bolster employment and provide a lift to risk assets, like stocks.

Fed watch: Rate hike would be a shocker

A rate hike tomorrow, however, is not expected by Wall Street, although investors expect the Fed to signal that one rate hike is still on the table for 2016. Futures markets are pricing in just a 15% probability that the Fed will hike rates Wednesday, according to CME Group, although the market is pricing in 50%-plus odds of a rate increase at the Fed's December meeting.

Investors are also gearing up for a meeting of the Bank of Japan Wednesday. The BoJ is still struggling to jump start growth and boost inflation in Japan. Investors are split on what the BoJ's next move will be, as they debate whether the BoJ will cut short-term rates, currently at -0.1%, further into negative territory. Investors will also watch to see if the BoJ boosts or tweaks its asset-purchase program or announces any fresh ideas to stimulate the economy.

"It's all about central banks," is the way Hans Mikkelsen of Bank of America Merrill Lynch summed up the market's focus.

In individual company news, Wells Fargo will be in the spotlight Tuesday, as CEO John Stumpf testifies on Capitol Hill before the Senate Banking Committee at 10 a.m. ET about the bank's creation of fake deposit and credit card accounts to meet sales targets.

Wells Fargo CEO refuses to push for exec pay clawback

In his prepared remarks released earlier today, Stumpf said he was "deeply sorry that we failed to fulfill our responsibility to our customers..." Wells Fargo (WFC) shares, which have been beaten down since the scandal hit, were 1.1% higher.

Wall Street was also watching the oil patch, where prices were again under pressure. U.S.-produced crude was down 69 cents, or  1.6%, to $42.61 per barrel.