The overall trend
If we look at the overall price action of the whole year for this index, we can see a clear bull market. S&P 500 has corrections or price dips that are normal for this index and which are usually fairly sharp. However, all these corrections have had a quick rebounce and they never fell below previous LOW. Even if we do not have a clear trendline for the overall structure, S&P 500 respects the previous lows and never falls below. This is still a rather strong bullmarket.
What about the current range?
As of now, index is moving in a range. Usually, if we see a movement in the range, the longer the asset moves in it, the bigger the break out of it can be seen. Thus, it is important that S&P 500 moves mostly in the upper part of the range, since there would be a bigger chance of upside movement. Luckily, that is currently happening. We have tested the ATH on two occasions, but it always retracted back down. The longer the price keeps testing this level, the higher the chance it breaks it.
It is also positive to see that in the last dip that we saw, S&P 500 did not create a double bottom, but only created a higher low. This also means that in my eyes, S&P 500 is still really bullish. Yet, I think the chances for the break of ATH in 2021 are 50/50. We can be sure that ATH will be broken soon, but whether that happens this year remains to be seen.