The Australian Securities and Investment Commission will not appeal the dismissal of its case against executives of the failed junior telco One.Tel.
The decision means ASIC will be up for a legal bill in excess of $14 million.
ASIC chairman Tony D'Aloisio said that "public interest considerations, cost and [the passing] of time were key factors in deciding not to appeal".
"We have reached the view that the Judge's decision turns on questions of fact and that there are no important points of law which should be reviewed on appeal," he said.
"Further, the case concerns conduct which occurred in 2001. A successful appeal would most likely result in a retrial causing a further significant delay to the final resolution of the matter."
The NSW Supreme Court dismissed civil proceedings against One.Tel founder Jodee Rich and its finance director Mark Silbermann in November last year.
Rich and Silbermann had been taken to task over their role as directors in the collapse of mobile services company One.Tel.
In December, the corporate watchdog lodged a notice of its intention to appeal the ruling.