I would say just 2 major reasons.
1) Bitcoin was deeply undervalued
2) The hype about the ETF approval.
We should wait another week and then decide whether Bitcoin appreciation has been substantial or not.
dude OP is talking about the past 12 months, the hype of ETF approval is a recent crap that is flying around only these days (less than a month) and the 150% increase in one month is pathetically small rise for bitcoin. check the history sometime and see how big we were rising each year. there is actually a good reply in the second comment you can refer too and also you can check bitcoinwisdon or bitcoincharts to see the history of all the past 8 years.
We're all perfectly aware that Bitcoin rose very high and by thousands of percent in the early days. That is normal for something that's new and still finding its place and level of attention.
Obviously Bitcoin still is, but it's completely different now to the rises before because we're actually dealing with seriously significant amounts of money now and the price can't just fly up and down in an instant, even though it is reasonably volatile.
As for reasons for the increase, I don't think that there was a significant change from the halving. Even though the new supply decreased, that should just be a decrease in the value of the mining industry and, while that may affect the price a little bit, it shouldn't be very significant. Generally I just think it's Bitcoin's increase in interest and its continued media attention. Maybe even its slight rise before was part of the reason for a continued price rise because of the media attention that it received and the fact that it hasn't died after the dumps from when there was the most hype about it around 2013.