1. Hashrate: increased security, higher mining difficulty
2. Selling pressure: it's safe to assume that most if not all miners need to sell the bitcoin they mine, for them to be able to pay for hardware and electricity(and probably taxes and stuff) and to remain a profitable business(or gig, for the smaller miners)

Mostly, it's just point #2. While prices are NEVER guaranteed to increase, this is the reason why a lot of people are assuming that the mining difficulty approximately a month and a half from now is going to pump bitcoin's price because the selling pressure from miners is going to be cut in half because the bitcoin that's going to be "minted" is going to be halved(hence why it's called the "halving").

For more information about the halving: https://www.bitcoinblockhalf.com/