Unofficial exchange points sold the dollar at VND23,450, down 0.15% from Thursday.
Vietcombank kept the rate unchanged at VND23,610 for the third day in a row.
Eximbank sold the greenback at VND23,580, and Techcombank VND23,605, unchanged from Thursday.
ACB let the dollar slide 0.42% to VND23,700.
The State Bank of Vietnam maintained its reference rate at VND23,602.
The dollar index was on track for worst week since Nov. 11, 2022 as dat on Thursday showed that U.S consumer prices fell for the first time in more than 2-1/2 years in December, offering hope that inflation was now on a sustained downward trend, Reuters reported.