This is the 11497th most frequent Spanish word.
extendiendo
"Extending" or "spreading."
The word 'extendiendo' is used here to mean stretching or lengthening out a physical object, in this case, the arms, to perform an action.
Estoy extendiendo mis brazos para alcanzar el estante superior.
I am extending my arms to reach the top shelf.
In this sentence, 'extendiéndose' illustrates the gradual spread or expansion (in a metaphoric sense) of light or visibility caused by the sunrise.
El sol está extendiéndose lentamente sobre el horizonte.
The sun is slowly extending over the horizon.
Here, 'extendiendo' denotes the act of broadening the sphere of influence or activity of the company, thus figuratively 'extending' its reach.