NEW YORK, Oct 26 (Reuters) - The negative impact of currency fluctuations on corporate results for North American companies fell in the second quarter of this year from the previous quarter, data from treasury and financial management firm Kyriba showed on Tuesday. The collective exchange rate hit, including on companies in the United States, Canada and Mexico, was $2.32 billion in the second quarter, compared with a $5.87 billion negative effect in the first quarter, Kyriba said in a report. S&P 500 (.SPX) companies are beginning to report results on the third quarter of 2021. "Supply chain disruption and inflation will test CFOs and treasurers" enterprise liquidity strategies and application of best practices to protect EPS, drive growth and reduce supply chain risk in the coming months," Kyriba"s Wolfgang Koester said in a statement.Kyriba said 35 North American companies reported currency impacts in the second quarter, compared with 77 in the first quarter and 28 in the fourth quarter of 2020. The U.S. dollar index fell 0.9% in the second quarter of this year. It gained 2% in the third quarter. A stronger dollar makes overseas sales less valuable when converted back into U.S. currency.