I think, because there's some news saying some markets will give BTCG (Bitcoin gold) to traders who store BTC in the market starting on 25th October, so many buy BTC and save it in hopes of getting BTCG.
This is more reliable reason. All people know that in 25 this month will be a fork in BTC. But there is no wallet for BTCG right no.how could this happen if there is no wallet so save BTCG. As we all know including me hope that fork will happen