CAMP HILL, Pa. — Rite Aid Corp. has added to a debt offering initiated earlier this year, drawing a favorable response from credit rating agencies.

The drug chain plans to issue $426 million in senior unsecured notes due in 2020 to help fund a refinancing of debt.

This month the company began a cash tender offer to buy $405 million of its 9.375% senior notes due in 2015. Any notes not tendered in the offerwill be called for redemption.

Rite Aid said that it aims to use the proceeds from the offering of 9.25% senior notes due in 2020 to help pay for the purchase of the notes maturing in 2015.

The tender offer of $998.75 per $1,000 of face value expires on May 31. Those who tender their notes by that date also receive a $30 consent payment per $1,000 of notes tendered.

According to Rite Aid, the new debt offering represents an add-on to its issuance in February of $481 million in 9.25% senior unsecured notes due in 2020. The proceeds of those notes were used to help fund the company’s purchase of about $405 million of 8.625% senior notes due in 2015.

After Rite Aid announced its latest debt refinancing, Moody’s Investors Service upgraded the chain’s Corporate Family Rating (CFR) to Caa1 from Caa2.

“The upgrade acknowledges Rite Aid’s ability to address its 2015 debt maturities by refinancing them until 2020 without increasing its interest expense,” the rating agency stated. “Moody’s believes that the refinancing of Rite Aid’s 2015 debt maturities somewhat reduces the likelihood of Rite Aid voluntarily choosing to restructure its debt over the medium term. However, Rite Aid’s Caa1 CFR reflects that the likelihood of a debt restructuring remains high, given its weak credit metrics and unsustainable capital structure.”

Moody’s also reiterated its “stable” outlook for Rite Aid.

“The stable outlook acknowledges Rite Aid’s adequate liquidity and lack of near-dated debt maturities,” Moody’s said. “Rite Aid’s next significant debt maturity is in 2014, when the remaining $1 billion of term loans is due. In addition, the stable outlook reflects our expectation that Rite Aid’s earnings will modestly improve but that the improvement will not meaningfully improve its credit metrics.”

Fitch Ratings maintained its “B-” Issuer Default Rating (IDR) for Rite Aid but upgraded its rating outlook for the drug chain.

“As a result of its recent debt refinancing activity, as well as the stabilization in its operating trends, Fitch has affirmed its ratings on Rite Aid and revised the rating outlook to ‘stable’ from ‘negative,’ ” Fitch stated.