Chief Justice John G. Roberts Jr. acknowledged in a report released Friday that the federal judiciary has work to do in ensuring that judges live up to their ethical responsibilities and in creating a harassment-free workplace.

But he politely told Congress it is work that judges can do on their own.

In his 2021 Year-End Report on the Federal Judiciary, the chief justice did not mention President Biden’s commission on reforming the Supreme Court or react to nascent congressional proposals to make drastic changes, such as expanding the number of justices or ending their lifetime tenure.

But he said the judiciary’s independence is best maintained by remaining free of interference from the political branches.

“The Judiciary’s power to manage its internal affairs insulates courts from inappropriate political influence and is crucial to preserving public trust in its work as a separate and co-equal branch of government,” Roberts wrote.

In the report, Roberts addressed “topics that have been flagged by Congress and the press over the past year.” Those included the failure of some judges to recuse themselves from cases in which they had a financial interest, and concerns about how the judiciary handles allegations of workplace harassment and discrimination.

Roberts referred to articles in the Wall Street Journal that said “between 2010 and 2018, 131 federal judges participated in a total of 685 matters involving companies in which they or their families owned shares of stock.”

He said that was “inconsistent” with a federal ethics statute that requires a judge to recuse in any matter in which he or she knows of a personal financial interest.

“Let me be crystal clear: the Judiciary takes this matter seriously,” Roberts wrote. “We expect judges to adhere to the highest standards, and those judges violated an ethics rule.”

But, he said, in context, that meant the judiciary had a “99.97% compliance rate.”

“For most of the judges involved (a total of 83 of the 131), the Journal reported one or two lapses over the nine-year period,” Roberts wrote. “Those sorts of isolated violations likely entailed unintentional oversights in which the judge’s conflict-checking procedures failed to reveal the financial conflict.”

Roberts said congressional intervention was not needed. The Judicial Conference and the Administrative Office of the U.S. Courts will dedicate themselves in the coming months to increasing ethics training for judges and researching new computer programs to detect potential conflicts in the cases that come before judges.

“The bottom line is that the Conference is taking the concerns seriously and has committed itself to the careful labor of addressing them,” he wrote. The Journal reported that Roberts said he had “serious constitutional concerns” about proposed accountability legislation in 2018.

Supreme Court justices are not covered by the same ethics policies, although the justices have said they voluntarily comply with them. Roberts is one of three justices — Stephen G. Breyer and Samuel A. Alito Jr. are the others — who own individual stocks. They recuse from cases, or sometimes sell the stock in order to participate, but they too have missed some cases.

Roberts did not address the view of some that judges and justices should avoid stock ownership.

The chief justice also acknowledged concerns about how the federal judiciary handles allegations of harassment and discrimination. He detailed steps that the judiciary’s leaders have taken to improve its reporting system, including the expansion of the Office of Judicial Integrity and the hiring of workplace relations directors in each of the federal circuits.

“Nevertheless, new protections could help ensure that every court employee enjoys a workplace free from incivility and disrespect,” Roberts wrote.

In support of a lawsuit filed by a former public defender in North Carolina, more than 20 current and former law clerks and employees of federally funded public defender’s offices and the Administrative Office of the U.S. Courts this summer offered firsthand accounts of a system that they say lacks protections and procedures to hold officials accountable.

A bipartisan group of lawmakers introduced legislation last summer that would establish whistleblower protections for judiciary employees and create a special counsel to investigate and report on misconduct complaints within the system.

“I appreciate that Members of Congress have expressed ongoing concerns on this important matter, and the Judicial Conference and its committees remain fully engaged,” Roberts wrote.

Roberts likes to lace his annual reports with history lessons, and this year’s reinforced his larger point.

He wrote about William Howard Taft, who served as president from 1909 to 1913, and then was chosen by President Warren G. Harding as chief justice 100 years ago.

“He knew well how to navigate the halls of Congress,” Roberts wrote, and “threw his considerable political heft into creating the mechanisms of self-governance for federal courts across the country.”

Taft “understood that criticism of the courts is inevitable, and he lived through an era when federal courts faced strident calls for reform, some warranted and some not,” Roberts wrote, adding, “The Congress of his era appreciated the Judiciary’s need for independence in our system of separate and co-equal branches, and it provided a sound structure for self-governance.”

Ann E. Marimow contributed to this report.