PREVIEW-What the Fed is considering at its meeting

* What: The Federal Reserve's policy-setting Federal Open Market Committee meeting

* When: Jan. 29-30; statement expected around 2:15 p.m. (1915 GMT) on Wednesday

* Expectations for 50 basis point cut in federal funds rate target; size of rate cut may depend on market conditions

By Tamawa Kadoya

NEW YORK, Jan 28 (Reuters) - After a tumultuous week for global stock markets that triggered an emergency rate cut by the Federal Reserve, Wall Street expects the central bank to follow through with more easing this week.

The biggest rate cut in more than 23 years last Tuesday signaled that the Fed will take an aggressive easing stance to prevent the "tail risks" of economic slowdown and financial market turmoil from spreading.

Most dealers expect the Fed to cut the benchmark federal funds rate by 50 basis points to 3.00 percent on Wednesday, while not ruling out a smaller 25 basis point reduction.

"The Fed will likely err on the aggressive side (of easing)," said Dean Maki, chief economist at Barclays Capital in New York. "It is very concerned about addressing downside risks quickly and ... risk is tied into the stock market."

The FOMC will also see some new voting members from this meeting, as regional Fed presidents rotate each year. Some analysts expect a dissent if the Fed cuts, as some members may be uncomfortable about inflation.

Following are some factors Fed policy-makers are considering:

MARKETS/CENTRAL BANK ACTION

The Fed slashed interest rates by three-quarters of a percentage point on Tuesday. It also cut the discount rate by 75 basis points to 4 percent.

The European Central Bank and the Bank of England kept rates steady this month.

On Dec. 12, major central banks including the Fed, ECB and the British, Canadian and Swiss central banks jointly announced steps to address rises in interbank lending rates.

As part of the initiative, the Fed created a Term Auction Facility to provide funds more smoothly to banks. It has auctioned $100 billion worth of funds through the facility, which would continue "as long as necessary to address elevated pressures in short-term funding markets."

Interbank market rates have fallen as year-end funding pressures have eased, and TAF provided an extra source of funding.