India, Sept. 15 -- The Federal Reserve is widely expected to raise interest rates on Wednesday, which would be its first rate hike in more than three years. Markets are strongly expecting a 0.25 percentage-point rate increase. Federal funds futures are pricing in about a 90% chance of a quarter-point hike, according to the CME FedWatch Tool.

The Fed's interest-rate decision will affect more than just Wall Street and stock prices. The federal funds rate also influences savings rates, credit-card interest, personal loans and, to a lesser extent, mortgage rates. For savers, a higher Fed rate can eventually mean banks offer slightly better interest rates on deposits. However, the increase is usually gradual, and basic bank accounts may still...