The technological innovation of a cryptocurrency is often the catalyst for the start of a markup or markdown period.

Consider the Bitcoin halving. This procedure halves the Bitcoin miner's payouts every 210,000 blocks.

It lowers incentives for mining Bitcoin on the network, which, in turn, limits the number of new Bitcoins created.

The perceived shortage of supply on the market will usually drive the price up if the demand is high enough to support it.

Bitcoin's halves have historically always marked the beginning of a new phase in markups, so this is a good indicator to keep an eye on.