Updates with mid-session prices

By Nikhil Sharma and Purvi Agarwal

May 21 (Reuters) - Latin American currencies were little changed, while stocks slumped on Wednesday, as concerns over the growing U.S. fiscal debt clouded the economic outlook, while a lack of any new developments on U.S. trade deals further dampened the mood.

A gauge for regional equities .MILA00000PUS fell 1.2% in conjunction with global stocks. The index was on track for its worst day in over a month. The MSCI regional currencies index .MILA00000CUS was slightly higher.

The dollar index =USD fell as investors grew concerned about U.S. President Donald Trump's sweeping tax bill, which could further inflate the country's debt. However, the Republicans were yet to unify around a path forward.

Wall Street's main indexes fell and long-dated Treasury yields jumped on Wednesday ahead of a debate around Trump's tax cut bill. .N

Analysts estimate Trump's tax bill would add $3 trillion to $5 trillion to the fiscal debt.

Investors were also on the lookout for more trade deals out of the U.S. before the 90-day tariff pause comes to an end, with hopes that more agreements could cushion economies from the impact of Trump's tariffs.

"People have been very heavily allocated to the U.S. for the past 10 to 15 years and are starting to face uncertainty, see how strong the dollar is, and are taking some profits off the table," said Malcolm Dorson, head of EM Strategy at Global X.

Most Latam currencies were lower, led by the Mexican peso MXN=, which fell 0.6%.

Stronger-than-expected retail sales figures, which showed a 4.3% rise in March, above estimates of a 2.2% increase, did little to boost investor sentiment.

A Reuters poll showed that the country's headline inflation rate likely accelerated in the first half of May, above the central bank's official target.

The local stock index .MXX however, jumped 0.4%, boosted by bottler FEMSA FEMSAUBD.MX and mining company Grupo Mexico GMEXICOB.MX.

Colombia's peso COP= was down 0.4%, tracking a fall in oil prices. O/R

Meanwhile, Brazil's real BRL= firmed 0.4% against the dollar, buttressed by resilient iron prices - the country's biggest export item.

The local benchmark stock index .BVSP, which is a heavyweight on the broader index, slipped 1.6%, with lender Itau Unibanco ITUB4.SA and power group Eletrobras ELET3.SA declining 2.2% and 1%, respectively.

"People who are looking to a potential weaker dollar are looking to EMs... but are country specific on who has that highest beta and Brazil's real is probably the most inversely levered to the U.S. dollar," said Dorson.

Chilean markets were closed in observance of a public holiday.

In other emerging markets, South Africa's rand ZAR=D3 reversed earlier gains to fall 0.1%, after the new budget projected a wider deficit and a higher debt. Earlier, the currency had hit a more than 5-month high.

The country's main stock index .JTOPI closed 0.7% higher, reaching a record high, after April inflation came in at 2.8% year on year, below the central bank's 3% to 6% target range.

Elsewhere, Israel's international bonds fell after reports of a potential Israeli strike in Iranian nuclear facilities sparked worries about a supply disruption in the Middle East. O/R

Bonds maturing in 2050 US46513JB429=TE fell more than 1 cent to the dollar.

Key Latin American stock indexes and currencies around 2000 GMT :

(Reporting by Nikhil Sharma and Purvi Agarwal in Bengaluru; Editing by Jane Merriman and Vijay Kishore)

((Nikhil.Sharma@thomsonreuters.com;))