Let's stop and think for a minute. There are buy orders and sell orders. The orders can be at market price or at a limit price. If there are no buyers at a price, the transaction does not occur. When sell volume is higher than buy volume in market orders, the price falls to find the next buyer.
Therefore, if the price does not fall, the buy and sell volume is equalized, and you just have heavy volume; not heavy sell volume. And if there is heavy sell volume with lower buy volume, the price must fall.
So the wording of the question is not really clear.
And, bullish sign is a sign that the future price will go up.
It's hard to predict what an all of a sudden heavy volume means.
We are interested in who is doing the buying and selling.
I'm more of an investor than trader, and traders tend to look at trends more than single instances, and investors look at company events and would be interested in what caused the spike in volume.
It means that if there are many sellers or sellers of large numbers that there are also buyers but not strong enough to move the price up. I take it as a support level as a good thing but not enough for bullish.
All those sales means people are buying stock, which means their expectation is the stock's value is going up and they're getting in at a good time.
Not bullish at all.
There cannot BE "heavy sell volume" without equally "heavy buy volume"…..shares cannot be sold unless there is somebody to BUY them….