Looking through the lens of stock investing, a Wall Street analyst says bitcoin is an attractive buy while it remains under pressure here.

"The mood in crypto is terrible right now," Thomas Lee, head of research at Fundstrat Global Advisor told CNBC. "Long-time holders are worried because they have big gains and they're worried about falling prices. But bitcoin is a great store value. It works really well. It's kind of boring, because it's not the latest and most exciting project. But it also is one of the most liquid ways to get exposure to crypto," he said on "Fast Money" Wednesday.

If an investor didn't hold stocks through the 10 best days for the S&P 500 each year, the annualized return would drop to 5.4 percent from 9.2 percent, Lee wrote in a Wednesday report.

Similarly, "the reason 'buy and hold' (or HODL) makes sense for BTC is that a handful of days each year account for the bulk of gains for BTC," Lee said. "For instance, in 2017, a total of 12 days represent the full-year return of BTC."

Bitcoin's astronomical rise over the last five years

Source: CoinDesk

"HODL" emerged from a misspelling of "hold" in an early bitcoin forum message that many speculated was written by a bitcoin trader who was thought to be drunk.

Investors in the traditional equity market are generally advised to buy and hold stocks, rather than trying to time trades at the cost of missing out on price gains.

However, it's not clear whether historical analysis on the decades-old stock market is appropriate for the far more volatile cryptocurrency that's less than 10 years old.

Lee found that in the five years since 2013, the full-year gains of bitcoin were achieved in an average of nine days. In comparison, he said the analysis for the S&P 500's performance stretches back to 1954.

Bitcoin has struggled to recover above $8,000 in the last three days and is down more than 40 percent for the year so far, after multiplying more than 13 times in price in 2017, according to CoinDesk's bitcoin price index.

The bitcoin misery index, an index coined by Lee to help investors determine when to buy, sell or hold the popular digital coins, is still low — around 28, Lee said.

"I don't think anyone who owns crypto should feel confident," he said. "But we still think bitcoin's in a bull market."

Investors who didn't hold onto bitcoin in the past would have suffered. Excluding its top 10 days of performance every year, bitcoin has fallen 25 percent annually from 2013 to 2017, Lee said.

"We think investors should be patient buyers of BTC here," he said.

In addition, Lee said, bitcoin's current low selling price, gives investors who aren't familiar with cryptocurrency a chance to study the industry, rather than jumping in feet first. He recommends, between now and the end of the year, putting fresh money into bitcoin rather than the market.

"As bad as it feels right now," Lee said. "Bitcoin has a lot more upside."

Lee was chief equity strategist at J.P. Morgan Chase before co-founding Fundstrat in 2014. He issued his first formal report on bitcoin in July and remains the only major Wall Street strategist to do so. On Wednesday, Lee maintained his midyear bitcoin price target of $20,000 and $25,000 for the year-end.