NEW YORK, Jan 16 (Reuters) - The U.S. Federal Reserve's balance sheet reached $4 trillion in the latest week as its latest stimulus program aimed to help the economy added more Treasuries and mortgage-backed securities to its holdings, central bank data released on Thursday showed.
On Jan. 15, the Fed's liabilities, which are a broad gauge of its lending to the financial system, rose to $4.029 trillion from $3.986 trillion a week earlier.
The Fed's third round of quantitative easing began in late 2011 when its balance sheet was less than $3 trillion.
On Dec. 18, the central bank decided to shrink its monthly purchases of Treasuries and MBS by $10 billion to $75 billion in January.
The Fed's holdings of Treasuries rose to $2.221 trillion as of Wednesday, up from $2.213 trillion the previous week.
The Fed's ownership of mortgage bonds guaranteed by Fannie Mae, Freddie Mac and the Government National Mortgage Association (Ginnie Mae) jumped to $1.525 trillion from $1.490 trillion a week ago.
The Fed's holdings of debt issued by Fannie Mae, Freddie Mac and the Federal Home Loan Bank system totaled $54.911 billion from $55.657 billion the previous week.
The Fed's overnight direct loans to credit-worthy banks via its discount window averaged $3 million a day during the week, slower than $12 million a day the previous week.(Reporting by Richard Leong; Editing by Chizu Nomiyama)