Newly purchased Series I bonds now pay 5.51% annual interest through April 30, according to CNBC. That is up from the 4.26% offered on bonds bought through October. These bonds are backed by the government and carry very little risk.

I bond interest has two parts, CNBC reports. The variable part, which resets every six months based on the consumer price index, rose to 4.08%. The fixed part rose to 1.40%, the highest since 2006, and stays the same for as long as you own the bond. Together, the 5.51% rate is the biggest since November 2022.

The new rate is "very attractive," said Ken Tumin, founder of DepositQuest.com, according to CNBC. He said the bonds look "very competitive" for the next six months against savings accounts and certificates of deposit.

People can buy up to $10,000 of electronic I bonds each calendar year through TreasuryDirect, CNBC reports. The interest is not subject to state or local taxes. But the money is locked up for 12 months, and you lose the last three months of interest if you cash out within five years.

"I always say [I bonds are] a secondary emergency fund," said David Enna, founder of Tipswatch.com. Experts say it is still wise to keep enough cash you can reach quickly, CNBC reports.

Not everyone is a fan. "For most of my clients, I bonds are more hassle than they're worth," said financial planner Eileen Olson. "The amount is too small to matter." She prefers other inflation-protected Treasury bonds called TIPS, which have no purchase limits.

This is news, not financial advice. The right choice depends on your goals and timeline, experts say.

Only CNBC has reported this so far, and NewsHabit hasn't seen independent confirmation.

What we know: New I bonds pay 5.51% through April 30, with a yearly purchase limit.
What we don't: What the rate will be after April, since part of it resets every six months.