One of the main reasons for Bitcoin's price increase today, April 21, 2025, is the impact of the Bitcoin halving event that occurred in April 2024.

During a halving, the reward for mining new Bitcoin is cut in half, which reduces the rate at which new coins enter circulation. This creates a supply shortage, and historically, it has led to significant price increases due to rising demand and limited supply.

Previous halvings in 2012, 2016, and 2020 were followed by strong price surges. Analysts predict that after the 2024 halving, Bitcoin's price could rise by over 160%, potentially reaching above $150,000 (source).

In addition to the halving effect, other contributing factors include:

Approval of Bitcoin spot ETFs in the U.S.

Expectations of interest rate cuts by the Federal Reserve

So, in short: reduced supply due to halving and strong market demand are driving today's Bitcoin price increase.