• An analysis of CryptoQuant data from both spot and derivatives exchanges shows the total volume of bitcoin held on all exchanges is 2019 lows.
• As of Aug. 26, bitcoin trading volume on all exchanges sat at 129,307 BTC, according to CryptoQuant. It's now off the March high of 3.5 million BTC by about 94%, according to the data provider.
• On Aug. 12, trading volume fell as low as 112,317 BTC, its lowest level since Nov. 10, 2018.

Bitcoin's trading volume hit its lowest level in almost five years this month as investors keep waiting for reasons to jump back into the market.

An analysis of CryptoQuant data from both spot and derivatives exchanges shows the total volume of bitcoin held on all exchanges fell earlier this month to its lowest level since 2018 and has struggled to rebound.

As of Aug. 26, bitcoin trading volume on all exchanges sat at 129,307 BTC, according to CryptoQuant. Earlier in the month, on Aug. 12, it fell to 112,317 BTC, its lowest level since Nov. 10, 2018. It's now off the March high of 3.5 million BTC by about 94%.

"Trading volumes decrease in bear markets as retail investors leave," Julio Moreno, head of research at CryptoQuant, told CNBC. "This happened during 2022 on most exchanges. As we progress further into a bull market, the trading volume may continue to pick up."

The price of bitcoin is still up 57% for the year and hovering at about $26,100, according to Coin Metrics.

It's been an excruciatingly quiet summer for bitcoin traders, but seasonality only accounts for so much of it. The U.S. regulatory crackdown on crypto combined with the end of the banking crisis in May (which accounted for much of its year-to-date gains) drove market makers and traders away – and they haven't had a reason to return.

Even after bitcoin's violent sell-off on Aug. 17 — the biggest one-day sell-off since the height of the FTX fallout in November — the market quickly became quiet again. Data shows long-term investors haven't been easily shaken by the recent weakness.

"Overall, [the] market remained dull waiting for a new catalyst and the overall market liquidity remained scant," Bernstein analyst Gautam Chhugani said in a note Monday of the last week in crypto trading. "This market is not necessarily bearish, but the participants remain disinterested to trade, as the market waits for catalysts" – specifically, in the form of decisions on any of the spot bitcoin ETF applications in line at the Securities and Exchange Commission.

Chhugani said that whatever ends up bringing some movement back to the market, investors' real opportunity "lies in staying the course into the new market cycle," which tends to coincide with the Bitcoin halving. The next one is expected to take place in spring of 2024. Cantor Fitzgerald echoed that emphasis on the long game.

"Although near-term catalysts may take many forms, we continue to believe in the long-term story of ongoing crypto adoption and bitcoin's staying power as an alternative asset and store of value," Cantor Fitzgerald  analyst Josh Siegler said in a note Monday.

—CNBC's Michael Bloom contributed reporting.

Correction: On Aug. 12, bitcoin trading volume fell to 112,317 BTC, its lowest level since Nov. 10, 2018. An earlier version of the story misstated the low and when the prior low occurred.