Frequency Electronics (FEIM) had the highest return between April 1, 1980 and August 31, 1980 by a US stock, returning 230.6%.

The average closing price for the Dow Jones Industrial Average (DJI) in December 1999 was $11,246.36. It was up 5.7% for the month. The latest price is $42,389.86.

Boeing (BA) had the highest return between January 1, 1978 and August 20, 1978 by a US stock, returning 150.2%.

The Dow Jones Industrial Average (DJI) returned 1.6% in January 2024.

Procter & Gamble (PG) had the highest return between October 1, 1978 and July 31, 1980 by a US stock, returning 3,015.5%.

Procter & Gamble (PG) had the highest return between October 1, 1978 and January 31, 1980 by a US stock, returning 2,689.2%.

Gold (XAU) has returned -97% in terms of Bitcoin (BTC) since January 1, 2017.

Sorry, I couldn't find pricing data for that day. The closing price for the Dow Jones Industrial Average (DJI) on December 31, 2015 was $17,425.03. It was down 0.9% for the day. The latest price is $42,389.86.

Tectonic Therapeutic (TECX) has had the highest return this year by a US stock, returning 4,842,400%.

The closing price for Tesla (TSLA) in October 2022 was $227.54, on October 31, 2022. It was down 10.6% for the month. The latest price is $269.38.

Electronic Arts (EA) returned 55.3% in 2013.

QQQ has returned 18.8% since February 1, 2024.

The closing price for Royal Bank of Canada (RY) in June 2003 was $9.37, on June 30, 2003. It was down 0.6% for the month. The latest price is $124.05.

Advanced Micro Devices (AMD) had the highest return between December 7, 2005 and February 6, 2006 by a mega-cap US stock, returning 52.8%.

CSX (CSX) had the highest return between December 7, 2005 and February 6, 2006 by a US stock, returning 1,842.2%.