The regulator announced in April last year that it would investigate the charity’s handling, reporting and response to serious allegations of misconduct and harassment.
Days later it appealed for anyone with information about alleged misconduct to get in touch.
It has not subsequently released any findings.
A commission spokeswoman told Third Sector the inquiry remained "open and ongoing".
She said: "We are working to progress our inquiry as quickly as we can, but it would be a disservice to those who have brought serious concerns to our attention were we to conclude the inquiry prematurely.
"We recognise the high public interest in the inquiry and its issues.
"We are committed to completing it thoroughly and robustly and as quickly as possible, and we will be publishing a full report setting out our findings and conclusions in due course."
Asked how many people had come forward in response to its appeal, the spokeswoman said she was unable to comment on the detail of ongoing inquiries.
The inquiry comes after previous engagement with the charity in 2015/16, when there was an anonymous complaint about the charity’s response to claims against senior staff and a serious incident report from the charity about misconduct and harassment claims.
Save the Children UK was hit by a number of revelations last year about past sexual misconduct by former senior employees, including inappropriate texts sent to female staff members by the charity's former chief executive Justin Forsyth.
There have also been allegations against Brendan Cox, the charity’s former policy director, of inappropriate behaviour towards women.
The charity commissioned an independent review in the wake of the allegations. In October the charity pledged to work with staff to review its organisational structure and operations after the review found that 28 per cent of staff had experienced either discrimination or harassment.
A Save the Children UK spokesman said this week: "Save the Children is working closely with the Charity Commission and we hope its report will be published soon."