For select to raise NO_DATA_FOUND you must use the strict option. The intent is when you expect exactly ONE row to be returned.
If the STRICT option is specified, the command must return exactly one row or a run-time error will be reported, either NO_DATA_FOUND (no rows) or TOO_MANY_ROWS (more than one row)...
SELECT qty,total_amount INTO STRICT v_qty,v_total_amount FROM stock_holdings WHERE account_id = 1 AND ticker_cd = 'XYZ';