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BRASILIA, April 24 (Reuters) - Brazilian stocks rallied to their highest close in more than six months on Friday, as optimism about the world's largest economy boosted appetite for riskier assets and lifted the national currency.

Sao Paulo's main stock index, the Bovespa .BVSP rose 2.12 percent to 46,771.79 points -- its highest close since early October 2008. The index has gained nearly 25 percent so far this year.

Wall Street stocks gained on Friday as better-than-expected results from companies including American Express and Ford Motor Co provided some relief to investors following months of negative economic news out of the world's largest economy.

"Despite still very bad economic data, company (results) are helping stock prices," said Andre Querne at a wealth management firm in Rio de Janeiro.

Brazil's national currency, the real (BRBY: Quote, Profile, Research), strengthened 1.26 percent to 2.191 reais per dollar as the greenback fell against a basket of currencies.

At the local stock exchange, financial firms were broadly higher. BM&F Bovespa (BVMF3.SA: Quote, Profile, Research), which operates Brazil's stocks, derivatives and commodity exchanges, jumped 4.6 percent to 9.39 reais. Itau (ITAU4.SA: Quote, Profile, Research) gained 2.5 percent to 28.59 reais while Banco Bradesco (BBDC4.SA: Quote, Profile, Research) added 1.2 percent to 26.26 reais.

Commodity shares also rose on the back of higher energy and copper prices. Vale (VALE5.SA: Quote, Profile, Research) gained 1.6 percent to 30.55 percent as copper prices jumped 3.94 percent. State-run Petrobras (PETR4.SA: Quote, Profile, Research) edged up 0.14 percent to 29.31 reais as oil prices jumped nearly 4 percent.

Commodity shares tend to gain on good news about the world economy, as faster-moving economies tend to consume more oil and metals.