Bitcoin prices have been surprisingly calm over the past few days. It's causing believers to think a further rally will ensue, but doubters are waiting for an imminent collapse.

Making matters more interesting? When Fed chairwoman Janet Yellen called Bitcoin a "highly speculative asset" on Wednesday. The comments sent bitcoin prices from roughly $17,200 to $16,200 in just a few hours, not unlike what happened to biotech stocks in the short-term when she criticized their valuation in 2014. (For what it's worth, biotech went on quite the run afterwards).

Yellen's comment about bitcoin also appeared to have an impact on Square (SQ)  , which fell roughly 5% Wednesday from its prior close.

In mid-November, the company announced that its Cash App -- which, for the record ranks higher than both PayPal (PYPL) and its Venmo app in the Apple (AAPL) App Store -- would run a pilot program allowing select users to buy and sell the cryptocurrency.

The company recently announced its plans to expand that program, causing many investors to assume it is going well.

Many investors tended to correlate Nvidia (NVDA) and Advanced Micro Devices (AMD) to the moves in bitcoin and ethereum prices, because the companies make graphic cards used to mine the cryptocurrencies. Unfortunately, for some traders, this correlation isn't as black-and-white as some investors would like.

Now bitcoin and Square are being compared in new ways.

Whether the comparisons are right or wrong doesn't matter; if investors are drawing a correlation between the two, Square stock will rally on bitcoin's good days and suffer on the bad. That's the likely impact to the stock in the short-term.

Is it fair? Not really, given that Square has an entire merchant business, along with other operations that are completely separate from what is likely a very small program it's running with bitcoin.

For now, however, there is one clear connection: bitcoin prices are up 1.3% to $16,622, while Square stock price is up 1.6% to $36.73 in early Thursday trading.

Apple and Nvidia are holdings in Jim Cramer's Action Alerts PLUS Charitable Trust Portfolio. Want to be alerted before Cramer buys or sells AAPL or NVDA? Learn more now.

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This article is commentary by an independent contributor. At the time of publication, the author had no positions in the stocks mentioned.

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