According to Reuters, the department also said it would conduct a small-value test auction using its contingency auction system on Aug. 17. More details about the test will be announced on Aug. 15.
A Treasury official told reporters that the test auction, in addition to Treasury's mock auctions, was prudent planning in case of technical difficulties or a cybersecurity incident.
In line with other small-value auctions, it is expected to be in the $25 million range, the official said.
On future coupon sizes, Deputy Assistant Secretary for Federal Finance James Clark said in a statement the department "plans to address changes in any seasonal borrowing needs over the next quarter through changes in regular bill auction sizes and/or cash management bills."
In its quarterly refunding announcement on Wednesday, Treasury said it would auction $62 billion in coupon debt next week.
On Monday, Treasury said it expects to issue $201 billion through credit markets during the July-September quarter, up $47 billion from its initial estimate in May.