Compute the maximum of the numeric field values of the records. This example aims to find the maximum open price of the ACWF ETF in the cf_etf_hist_price index. The maximum open price of the ACWF ETF is 29.51:

"query": { "match": { "symbol": "ACWF"}},"aggs": {"maximum_open_price": {"max": {"field": "open"}}}