Prediction: If This 1 Policy Changes, Bitcoin and Ethereum Will Soar

As boring as many people find it, tax policy can move markets even more than news of a fancy new product coming out. When administrations change what people keep after the government takes its cut, they change how much risk investors are willing to take and how long they're willing to hold.

And right now, Japan is flirting with a very big tax change that has big implications for all cryptocurrencies, especially the majors like Bitcoin (CRYPTO: BTC), Ethereum (CRYPTO: ETH), and Solana (CRYPTO: SOL). If the policy ends up being implemented, it could spark a new boom. Here's what's being considered and why I predict that it will be very bullish if it happens.

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This crypto tax overhaul could unlock a vast new market

For years, Japan has combined strict consumer protections with a strict tax regime for crypto holders.

Under the existing rules, most personal crypto gains are treated as miscellaneous income rather than capital gains. That means that profits are taxed at between 5% to 45%, plus a flat 10% "inhabitant tax," for an effective tax ceiling near 55% on large gains. There are also tight limits on tax offsetting crypto losses.

But at the moment, the nation's lawmakers are weighing whether to slash the effective tax rate on cryptocurrency gains down to a flat 20%, similar to the rate on stocks and investment funds. Politicians in the National Diet, Japan's deliberative and legislative body, have signaled support for the change, perhaps due to seeing digital assets as part of a broader strategy to try to revive the country's economic growth while also keeping more capital onshore instead of letting it flow into attractive international markets like U.S. and China. Industry leaders expect that if the reform is approved, it will also open doors for the issuance of local crypto exchange-traded funds (ETFs) and clarify how asset managers can package digital assets for retail investors.

Japan is not a niche market; as of May 2025, roughly 12.4 million Japanese residents already held or use cryptocurrency, with more than 4.26 trillion yen (about $27.5 billion) held in custody on domestic platforms. That capital base has grown very quickly from about 5.6 million users in 2022, reflecting both progress toward regulatory normalization and frustration with low yields on savings as inflation has outpaced wage growth.

So, the tax change would radically adjust after-tax math for those investors, and it would almost certainly lead to a deluge of investment into crypto from investors who were previously too discouraged by the tax structure to participate. When paired with the country's already-rapid pace of growing crypto participation, the effect on leading crypto prices could be substantial, especially over time.

What a friendlier Japan means

When barriers to investment are removed, capital tends to seek the path of least resistance toward generating a return where it couldn't before. For Japanese households and financial institutions that have been sitting on the sidelines, that path will probably run straight through the largest, most global crypto assets first, specifically Bitcoin and Ethereum, with Solana and other majors likely picking up a solid tailwind as well.

Japanese banks and other financial businesses are already exploring whether they will be allowed to hold Bitcoin directly and offer custody and related services. If the tax code aligns with stocks, levying 20% on capital gains, Bitcoin becomes much easier to justify as a long-term allocation for tax-aware Japanese investors who already understand equity investing.

Ethereum would play a different role, as its investment thesis holds that it's the default base layer for the decentralized finance (DeFi) ecosystem. For Japanese asset managers, a flatter tax regime may make it easier to launch Ethereum-based financial products that combine its potential appreciation with a yield from staking or on-chain lending activities, though these are more complex and carry additional risk stemming from both smart contracts and regulators.

Of course, this catalyst is not necessarily a slam dunk. The tax proposal might be watered down in the legislative process, or delayed or perhaps even rejected entirely. Even if it passes, Japanese households are older on average and historically have been more conservative investors, so it is not obvious that they will meaningfully increase their crypto exposure immediately.

For investors outside Japan, the way to think about this policy is as a potential bonus tailwind that could start fairly soon. This isn't something to build a thesis on, but if the legislators vote to implement the tax cut, just be aware that it's another vote in favor of buying these leading crypto assets.

Alex Carchidi has positions in Bitcoin, Ethereum, and Solana. The Motley Fool has positions in and recommends Bitcoin, Ethereum, and Solana. The Motley Fool has a disclosure policy.