You should also accept: "We do not invest in the stock market."
"At" the stock market instead of investing "in" the stock market - does this mean that you have to be physically present inside the building of the stock exchange? Some prepositions are more difficult than others.
I'm not a native speaker, but here is my input: "bursă de valori"= stock exchange and "bursieră"/"bursă" = stock market.
Stock exhange înseamnă bursă de acțiuni...sunt multe feluri de burse ; burse de mărfuri, de animale, agricole, metale prețioase, bursă valutară, șamd . Deci ați greșit traducerea !
merge si la plural: burse!!
This is a bad translation. It means that we do not go in person to the stock exchange to invest.