I think in the beginning of a stock market crash it could sell off a bit too because of general panic. However, when it comes to more QE or a currency crisis, BTC will benefit, is proven already in the Greece, Cyprus and Brexit crisis (BTC spiked). Also in Venezuela, India and Zimbabwe the demand for BTC is huge. Furthermore, when bankruns happen or the recession gets deep and long BTC will benefit I suspect. Anyway, BTC just had a heavy crash, so is heavily undervalued now, so the downside is limited. The Stockmarket has risen for 10 years and is heavily overvalued.