Five local analysts forecast last month's surplus at a median of $367 million. The average outlook was for a surplus of $431.6 million, with analysts' estimates ranging from $237 million to $714 million.
The economists also cited a slowdown in the rate of imports, which have been subject to a raft of controls and curbs as the center-left government battles to prop up the trade surplus.
An incipient slowdown in Latin America's No.3 economy may also be starting to weaken demand for imported products.
"There's a slowdown in car exports to Brazil ... and that's in turn affecting imports of car parts," said economist Rodolfo Rossi, from the Rossi and Associates consulting firm.
"The import restrictions that the government's been imposing since February, with the system of advance import permits, brings with it the possibility of reduced manufactured exports," he added.
Since the start of the month, almost all purchases from abroad must get advance permission from the government.
A shrinking surplus is especially sensitive for President Cristina Fernandez because she plans to tap billions of dollars from central bank foreign reserves to pay debt for the third consecutive year.
In 2011, the surplus narrowed 11 percent even as the rate of import growth slowed sharply at the end of the year. In January 2011, it was $513 million. (Reuters)
