What happened

Shares of Grayscale Bitcoin Trust (GBTC -3.90%), a fund that allows investors to indirectly own bitcoin, were falling hard on Thursday as the price of bitcoin keeps sliding. As of 2:15 p.m. EST, shares of Grayscale Bitcoin Trust were down 10%. And bitcoin was down 9% over the past 24 hours, according to CoinDesk.

So what

Since Grayscale Bitcoin Trust only holds bitcoin, it's logical that the two would go up and down together. In a perfect world, Grayscale Bitcoin Trust would trade perfectly in line with the value of its bitcoin tokens. But this isn't the case. As bitcoin rises, it creates demand for this alternative asset. But not all investors are willing open an account with a cryptocurrency exchange. Some would prefer to own it indirectly, and Grayscale Bitcoin Trust is one of the only options for that.

Stacks of physical, golden coins display the bitcoin symbol.

Image source: Getty Images.

Now what

At times, this situation creates outsized demand for shares of Grayscale Bitcoin Trust, and they trade at a premium to its underlying bitcoin assets. However, right now it's getting much closer to its net asset value (NAV). The fund's website updates daily at 4 p.m., so these numbers are from yesterday. But the NAV of Grayscale Bitcoin Trust was $33.26 per share at its latest update. 

The price of bitcoin was about $35,000 at 4 p.m. EST yesterday. Right now it's about $32,300. So the NAV for Grayscale Bitcoin Trust has declined a little more than 10% to about $30 per share. For comparison, shares are trading around $32 per share. This about the closest it's been in a while. 

If you've been considering an investment Grayscale Bitcoin Trust, it's certainly becoming more attractive. However, if you invest, you're assuming the price of bitcoin will head higher in the long term. Predicting the future movement of cryptocurrencies is a hard thing to do.