The Washington Post’s chief executive told the newsroom on Friday that it would no longer endorse presidential candidates, breaking with decades of precedent at the newspaper.

“The Washington Post will not be making an endorsement of a presidential candidate in this election,” wrote Will Lewis, The Post’s chief executive. “Nor in any future presidential election. We are returning to our roots of not endorsing presidential candidates.”

The Post has endorsed presidential candidates since 1976, Mr. Lewis wrote, when it gave its stamp of approval to Jimmy Carter, who went on to win the election. Before that, it generally did not make presidential endorsements, though it made an exception in 1952 to back Dwight Eisenhower.

Questions about whether The Post would endorse a candidate this year had spread for days. Some people speculated, without any proof, that the paper’s billionaire owner, Jeff Bezos, was being cowed by a prospective Trump administration because his other businesses have many federal government contracts.

Mr. Bezos made the decision not to endorse presidential candidates after a debate among senior Post leaders, according to a person familiar with the talks.

Mr. Lewis, in his note to the staff, said little about how The Post had arrived at its decision, adding only that it was not “a tacit endorsement of one candidate” or “a condemnation of another.” He referred to an editorial the paper published in 1960 that said it was “wiser for an independent newspaper in the nation’s capital” to avoid an endorsement.