noun
all-time high; record high; new high
Used in financial contexts for the highest price a security, commodity, or index has ever reached. Antonym: 最安値 (さいやすね, all-time low).
Antonyms: 最安値
日経平均株価が最高値を更新した。
The Nikkei stock average hit a new all-time high.
この銘柄は
This stock reached a year-to-date high today.
高値 simply means 'high price' or 'high level', not necessarily a record. 最高値 specifically means the highest price ever.
Compound of 最高 (さいこう, 'highest') + 値 (ね, 'price'). The reading さいたかね is a standard compound reading.