* Jan-April trade balance swings to deficit
* Focus on Q1 GDP numbers due on Tuesday
* Stocks up as global equities rally (Updates rand; add bonds, stocks closing prices)
JOHANNESBURG, May 31 (Reuters) - South Africa's rand weakened against the U.S. dollar on Thursday after the country's trade balance for the year so far swung to a deficit compared with a surplus last year, pointing to the fragility of the economic rebound.
Stocks rose, supported by technical factors after momentum indicators showed the market was near oversold levels. It was given a further shot by a global equities rally spurred by Chinese data and renewed efforts in Italy to form a government.
At 1520 GMT, the rand traded at 12.6900 per dollar, 1.34 percent weaker than its close on Wednesday.
South Africa's revenue agency said the trade balance for January to April was a deficit of 17.65 billion rand ($1.39 billion), compared with a surplus of 8.52 billion for the comparable period in 2017.
The data ignited concerns that the economic growth outlook remained uncertain despite an uptick in sentiment.
"Net trade has been quite disappointing thus far in 2018 and will likely be a drag on first-quarter GDP," said Elize Kruger, an economist at NKC African Economics.
"We forecast a wider current account deficit of 2.8 percent of GDP for 2018 compared to deficit of 2.3 percent of GDP in 2017."
First-quarter GDP numbers are due for release on Tuesday. The economy expanded 3.1 percent in the last quarter of 2017.
In fixed income, the yield for the benchmark government bond due in 2026 rose 1.5 basis points to 8.555 percent, reflecting weaker prices.
On the bourse, the benchmark Top-40 index added 1.01 percent to 49,783 while the wider all-share index climbed 1 percent to 56,157.
Precious metals producer Sibanye-Stillwater added over 2 percent in the session after it said it was exploring debt-cutting options while ruling out tapping shareholders for funds. But just before the market closed it slipped into the red to end 0.13 percent lower.
$1 = 12.6653 rand Reporting by Olivia Kumwenda-Mtambo and Ed Stoddard Editing by Robin Pomeroy