BENGALURU, March 20 Reuters Indian shares reversed early gains ahead of the U.S. Federal Reserve39;s interest rate decision, while Eicher Motors jumped after UBS upgraded the stock.

The bluechip NSE Nifty 50 index shed 0.45 to 21,718, while the BSE Sensex fell 0.44 to 71,699.09, as of 1051 a.m. IST.

They had risen about 0.3 each at the open, after sliding to a fiveweek low in the previous session.

Markets have resumed a corrective tone with the benchmark Nifty slipping below a crucial support zone of 21,850 levels, said Ajit Mishra, senior vice president of research at Religare Broking.

Twelve of the 13 major sectoral indexes declined. Financial stocks, the highestweighted sector, fell 1.

The broader, more domestically focussed smallcaps and midcaps dropped 1.1 each.

So far in March, they are down about 10 and 6, respectively, compared to a 1.2 drop in the Nifty 50.

Small, midcaps could see further pressure due to earnings headwinds amid concerns of elevated valuations, said Prateek Parekh and Priyank Shah, analysts at Nuvama Institutional Equities.

Eicher Motors gained 4.3 after UBS upgraded the motorcycle maker39;s shares to buy from neutral, and raised its price target citing likely gains from new Royal Enfield models and attractive valuations.

Tata Steel and Hindalco Industries fell 3 each, following a drop in global metal prices and a rise in the U.S. dollar. The Nifty metal index fell 1.7.

Asian shares were hesitant on concerns the Fed could signal a…