- Rates now: Standard 8%, Premium 10% on the first $50,000, Private 12% on the first $200,000; above the cap, 8%.
- After the boost: the app says the rate returns to 4%.
- End date: the app says mid-2027 and the Reserve page 1 July 2027, but the legal terms still say 31 December 2026 or $100 million in total reserves, whichever comes first.
- Not a deposit: no deposit insurance, no principal protection, and the rate can change to 0%.
What the KAST app shows (2026-10-13)
At 18:45 JST on 2026-10-13 the KAST app on our account showed this USD Reserve Account screen:
- "Enjoy boosted rates until mid-2027. Earn 8% reward rate now, returning to 4% after."
- No lock-ups, no limits on access; rewards are fully funded by KAST.
- Daily cash rewards, credited automatically.
- 12% annual reward rate with the Private plan.
- Move funds instantly or spend directly from Reserve with your card, with no fees or lock-ups.
Rates and caps
Source: KAST Reserve page and the help article Reserve Reward Rates and Membership Comparison (updated 2026-09-09), both checked 2026-10-13. The help centre stresses that Reserve Rewards "are not interest, APY, yield, or an investment return" and are funded by KAST as a promotional benefit.
On the Reserve page's own example, $500,000 on Premium earns up to about $1,639 a year (10% on the first $50,000, then 8%). The Premium fee is $1,000 a year, so compare the extra 2 percentage points with the fee before upgrading: on $50,000 the extra 2% is $1,000, the same as the fee. Our Japanese guide works through the breakeven in detail.
When does the 8% end? The sources disagree
- App (2026-10-13): boosted rates until mid-2027, then 4%.
- Reserve page: "Offer ends 1 July 2027".
- Help centre (updated 2026-09-09): 30 June 2027 or $100 million in total reserves, whichever comes first.
- Reserve terms (effective 2026-08-20): "The Promotional Rate will apply through 31 December 2026 or until total platform reserves reach $100 million, whichever occurs first."
Where the terms and marketing differ, the terms are the legal document. Plan for the possibility that the boost ends on 31 December 2026, or earlier if total reserves reach $100 million; the terms say the promotion can end without a fixed notice period for that reason.
What Reserve is not
The terms say the USD Reserve Account is not a bank account, deposit account, investment account or principal-protected product, and is not covered by deposit insurance. The applicable reward rate may change, including to 0%. The contracting entity is KAST Tech in Anjouan, Comoros. KAST publishes no country list for Reserve; whether it appears depends on your account's Accounts tab.
For card fees and memberships see the KAST Card review; for cashback by tier see KAST card cashback; for availability see KAST supported countries; if you are new, the KAST referral code gives 10% off a first paid membership.
FAQ
What rate does KAST Reserve pay?
On 2026-10-13 KAST's Reserve page lists Standard 8%, Premium 10% on the first $50,000 and Private 12% on the first $200,000; balances above the cap earn 8%. These are promotional reward rates funded by KAST, not interest.
When does the 8% boosted rate end?
The sources differ. The app screen on 2026-10-13 said boosted rates last until mid-2027 and then return to 4%. The Reserve page says the offer ends 1 July 2027 and the help centre says 30 June 2027. The Reserve terms still say through 31 December 2026 or until total reserves reach $100 million, whichever comes first, and the terms prevail.
Is KAST Reserve a savings account?
No. The terms say the USD Reserve Account is not a bank, deposit, investment or principal-protected product and is not covered by deposit insurance. KAST says the rate can change, including to 0%.
Can I spend from Reserve with the KAST card?
Yes. The app says you can move funds instantly or spend directly from Reserve with your card, with no fees or lock-ups.