On 8 August, the source wrote (citation):

[...] In the second quarter of 2019, the FHFA announced the discontinuation of the monthly interest rate survey (MIRS) that produced the interest rate data used in the HOI calculations. As a result of the loss of this critical input, NAHB will delay the release of the HOI for the second quarter of 2019 in order to find an acceptable replacement for the FHFA data on interest rates. We expect to be able to produce and release results for both the second and third quarter on the scheduled third quarter release date on Nov. 7, 2019.

The series reside in the historical catalog (United States » Real Estate » Residential » National Association of Home Builders (NAHB) » Housing Opportunity Index (HOI)) and include, for example:

• XNAHBHOIQ.IUSA       = Housing: Housing Opportunity Index, (%, NSA)
• XNAHBHOIQ.IUSA_MBIL  = for Billings, MT MSA
• XNAHBHOIQ.IUSA_DMDET = for Detroit-Dearborn-Livonia, MI Metropolitan Division

See also

• Discontinued Data: U.S. subnational - FHFA MIRS (May 2019)
• Discontinued Estimates: U.S. subnational - Mortgage effective interest rate for states (Aug 2019)