If you're a cryptocurrency investor, chances are you're feeling pretty good about things right now -- especially if your investments are heavily tilted toward bitcoin (BTC) and ethereum (ETH). Both have posted strong gains in 2025 despite some choppiness earlier in the year.
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Those are the two most obvious cryptos to keep an eye on during the final few months of the year. But they're not the only ones. Here are four cryptocurrencies investors should watch this fall, according to experts.
Also see which altcoins are the best to invest in right now, according to ChatGPT.
No list of cryptocurrencies is complete without mentioning the biggest of them all. Although bitcoin has experienced some volatility in 2025, its price was still up more than 19% year to date through Sept. 2.
Historically, September has been bitcoin's weakest month, according to J. Ryan Smolarz, MD, MBA, owner of "The Medicine and Money Show" and founder of STOR Partners, a blockchain-backed system.
Things might be different for bitcoin this year, however.
"There are chances that large institutional investors could be silently building their positions, [which] means the dips may be short-lived," Smolarz told GOBankingRates. "It is being predicted that the Federal Reserve's upcoming decisions on interest rates can also affect the scenario significantly."
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One of the main things to keep an eye with solana (SOL) is its validator distribution, according to Chad Cummings, an attorney and CPA at Cummings & Cummings Law who previously worked in finance and tax with American Airlines, PwC and JPMorgan Chase.
"Solana's validator centralization and history of multi-hour network outages pose systemic risk if confidence drops during a sell-off," Cummings told GOBankingRates. "Despite upgrades, validator distribution remains highly concentrated."
As of August 2025, he said, more than 33% of Solana's stake was controlled by fewer than 30 validators, making the chain "vulnerable to coordinated disruption."
The world's second-biggest crypto has had plenty of highs and lows in 2025 -- just like bitcoin. But like bitcoin, ethereum has rallied since an April sell-off and its price was up nearly 30% year to date as of Sept. 2.
Smolarz said it's "almost impossible" to overlook ethereum when discussing crypto innovation -- although it faces "shaky September" risks similar to those facing bitcoin. In ethereum's case, those risks should be offset somewhat by "strong fundamentals."
"Over the years, the ETH network has been improving with regular updates and institutional money that keeps flowing, mostly through ETFs," Smolarz said.
Arbitrum's treasury governance could trigger "regulatory scrutiny" under the new decentralized autonomous organization (DAO) reporting requirements imposed by the Guiding and Establishing National Innovation for U.S. Stablecoins (GENIUS) Act, Cummings said.
That scrutiny is largely due to the fact that arbitrum (ARB) governs more than $2.5 billion in its DAO treasury, which means it must "register beneficial owners and file annual disclosures" with regulators.
"Failure to comply could classify ARB governance participants as unregistered investment advisers or fiduciaries under U.S. law," Cummings said. "The moment the DAO executes an off-chain agreement or grants decision-making power to a small multisig group, it may trigger ERISA or SEC jurisdiction."
This article originally appeared on GOBankingRates.com: 4 Cryptocurrencies Investors Should Watch This Fall