AGNC ▲ +0.2% - AGNC Investment Corp. $AGNC AGNC - AGNC Investment Corp. to Join the S&P MidCap 400 Index AGNC Investment Corp. rose 0.2% following news that it will be added to the S&P MidCap 400 Index, a move that typically brings increased institutional demand as index funds and ETFs rebalance their holdings to include the stock. 16-SEP-2026 04:01 PM ET