Less than a week ago, bitcoin’s price set a new all-time high at $19,920.53. However, the oldest cryptocurrency is still struggling to break above the $20,000 level.

The reason that milestone remains elusive, according to analysts and traders, is simple: There are too many sell orders very near the $20,000 level because some bitcoin holders are afraid of near-term sell-offs. That price point is particularly significant because it’s roughly where the market topped out in the late 2017 rally that saw bitcoin quadruple in price within two months, only to collapse by 70% within the subsequent two months, its biggest (at the time) price correction.

“A huge [number] of sellers are offering orders near the $20,000 level, which has no doubt created a strong resistance level,” Simon Chen, executive director of investment and trading at Hong Kong-based crypto lender Babel Finance, said. “People are trying to sell at this level based on what happened during the 2017 bull market.”

Bitcoin prices versus trading volumes. Source: Tradingview

For some, similarities to 2017 are hard to ignore, particularly the speed by which bitcoin made new record prices.

The $20,000 level “is like psychological warfare for many,” said Lingxiao Yang, chief operating officer at crypto quant firm Trade Terminal. “It only took about a month for bitcoin to go up from around $14,000 to the new all-time high.”

But Yang also said that this emotional element has largely been reflected on the retail investors’ side, while more institutions are in the “buy the dip” mindset.

Market fundamentals are also weighing on bitcoin. Data from crypto analytics site CryptoQuant indicate major bitcoin holders, or whales, have not been withdrawing bitcoin from exchanges.