Net foreign purchases of long-maturity U.S. securities totaled $36.9 billion in March, following purchases of $5.4 billion the month before, according to a U.S. Treasury Department report released Friday.

The monthly Treasury report highlights cross-border acquisitions of securities with maturities of more than one year, including non-market transactions such as stock swaps and principal repayment on asset-backed securities.

The closely watched figure, excluding transactions that don't occur on an open market, recorded net purchases of $55.8 billion in long-term U.S. securities, after purchases of $22.0 billion in February, according to the monthly Treasury International Capital report, known as TIC.

The report's most comprehensive category, "monthly net TIC flows," includes non-market flows, short-term securities and changes in banks' dollar holdings. This measure of net foreign capital inflow was $23.2 billion in March, versus an outflow of $91.1 billion the previous month.

Financial market analysts consider the monthly data from the Treasury Department to be a significant but imprecise gauge of how easily the U.S. can finance its trade deficit. The February TIC flow compares with the $27.58 billion trade deficit during the month.

Within the long-term securities category, foreign net purchases of U.S. Treasury notes and bonds totaled $55.3 billion in March, compared with net purchases of $21.6 billion the month before.

Private foreign investors bought a net $26.7 billion in Treasury notes and bonds in March, after buying $23.6 billion in February. Meanwhile, foreign official institutions such as central banks bought a net $29.0 billion of these Treasurys, compared with net sales of $2.0 billion the month before.

Net foreign sales of debt issued by U.S. government-sponsored agencies like Fannie Mae (FNM) and Freddie Mac (FRE) totaled $15.6 billion in March, compared with $1.1 billion in purchases in February.

For U.S. equities, net foreign purchases totaled $13.2 billion in March, compared with sales of $5.1 billion the previous month.

For corporate bonds, net foreign purchases were $3.5 billion, versus purchases totaling $3.3 billion the previous month.

China remained the largest holder of U.S. Treasury securities, having surpassed Japan late last year. China increased its holdings to $767.9 billion in March. Japan, the second-largest holder of U.S. Treasurys, increased its holdings to $686.7 billion.

The TICs data, typically released around the 11th business day of the month, can be found on the Treasury's Web site at: http://www.treas.gov/tic. With each monthly release, Treasury revises the previous month's data as well.

The next report, covering April, is scheduled for release June 15.

-By Maya Jackson Randall, Dow Jones Newswires; 202-862-9275;