Jan 16 (Reuters) - Three of the six largest U.S. banks announced new bond issues on Tuesday, kicking off an expected heavy week for new bank debt.

Wells Fargo is tapping the bond market on Tuesday for either or both of fixed and floating-rate notes, in addition to senior unsecured fixed-to-floating rate notes.

Meanwhile, JPMorgan and Morgan Stanley announced they are seeking to issue four tranches with different maturities of senior unsecured notes.

The banks did not disclose the exact amount of debt they are seeking. Both deals are expected to price on Tuesday.

The deals follow a long list of Friday earnings releases from these and other global systemically important banks (GSIBs).

In addition to Wells Fargo, JPMorgan and Morgan Stanley, other banks that reported fourth quarter earnings on Friday and Tuesday include Bank of America, BNY Mellon and Citigroup and Goldman Sachs.

January has historically been the biggest month for banks to issue bonds. According to data from Informa Global Markets, the last seven Januarys have seen an average $22.58 billion in issuance from the "Big Six" banks - JPMorgan, Citi, Bank of America, Wells Fargo, Goldman Sachs and Morgan Stanley.

The outlier was last January, which saw only $9 billion raised by the Big Six, according to the Informa data.

At least 11 investment-grade (IG) bond offerings are expected to price on Tuesday including Wells Fargo, JPMorgan and Morgan Stanley.

These include a $500 million three-year bond for cereal maker General Mills and a $400 million 10-year senior note for real estate investment trust Extra Space Storage .

The expected heavy supply comes despite the holiday-shortened week. For the week of Martin Luther King Jr Day, the average investment-grade bond supply dating back to 2016 has been $24.6 billion, according to Daniel Krieter, director of fixed income strategy at BMO Capital Markets.

Banks are expected to be particularly active in debt issuance this month, as they look to get ahead of new regulatory requirements to maintain higher capital reserves.

"That makes a projection of $35bn from U.S. GSIBs in January reasonable in our estimation, with the majority of that supply expected to come this week," Krieter wrote in a Tuesday note. (Reporting by Matt Tracy, Editing by Nick Zieminski)