FRANKFURT—Top officials from the European Central Bank met regularly with representatives from financial institutions over the past 15 months, including one meeting that occurred on the same day as a key gathering of the ECB’s governing board, according to documents released Monday by the ECB.

The disclosure of the appointment calendar of the ECB’s six-member executive board, as part of a public-access request, came amid changes to the ECB’s communications policies following the release of market-sensitive information in May to a closed-door conference that included hedge-fund managers.

Such meetings aren’t unusual, but the calendar points to the delicate balance for officials who benefit from the market intelligence provided by private-sector economists and investors but must also avoid the perception that individual banks are benefiting from this access.

According to the calendars, ECB executive board member Benoît Coeuré met with representatives of BNP Paribas SA on the morning of Sept. 4, 2014, hours before the ECB announced a reduction in its interest rates and the creation of a new four-year lending program for banks.

The day before that two-day meeting began, Mr. Coeuré met with UBS Group AG on Sept. 2, as did another executive board member, Yves Mersch, according to the meeting calendars. Mr. Mersch also met with BNP Paribas on Sept. 4 last year, although that was after the ECB meeting concluded.

“The ECB does not operate in a vacuum. Regular contacts with different groups, including representatives from the financial sector help us understand the dynamics of the economy and financial markets. We make sure that at such meetings no financial market-sensitive information is disclosed,” an ECB spokeswoman said.

BNP Paribas and UBS declined to comment.

Details of these meetings were first reported by the Financial Times.

The meetings with representatives from the financial industry aren’t unusual. The calendars of other ECB officials, including ECB President Mario Draghi, show occasional meetings with banks and other financial institutions and meetings with academics, government officials and the media.

ECB officials are expected to refrain from commenting on monetary policy in the week before meetings of the governing council. For that reason, officials typically shy away from making public speeches then, although these restrictions don’t apply to one-on-one-meetings as long as market-sensitive information isn’t disclosed.

“The quiet period refers to public communication ahead of monetary policy Governing Council meetings. The same underlying principles—guarding against signaling future monetary policy—are of course applied to bilateral meetings,” the ECB spokeswoman said.

Last week, the ECB said it would begin publishing the meeting calendars of its executive board members early next year, and they will refer to the period from Nov. 1 and will be published with a lag of about three months.

The ECB said the first release would be in February of next year.

In the U.S., the Federal Reserve in June 2011 adopted a communications policy stating that members of its top policy-making committee “will strive to ensure” they don’t provide any profit-making entity “with a prestige advantage over its competitors.”

Policy makers “will consider this principle carefully and rigorously” when meeting with “anyone who might benefit financially from apparently exclusive contacts” with Fed officials, according to the policy.

The Fed regularly discloses its communications with the public, including financial firms, related to the continuing implementation of the 2010 Dodd-Frank Act.

The ECB faced criticism of its communications with the public earlier this year after Mr. Coeuré disclosed in a closed-door speech that the central bank would temporarily front-load its purchases of government bonds to account for an expected summer lull in market liquidity. The evening speech, which wasn’t posted on the ECB’s website until the following morning, sparked a rally in the government-bond market and weakened the euro.

It also prompted concerns that the attendees of the event, which included hedge-fund managers, had an unfair edge with access to market-sensitive information.

The ECB blamed the delay on “an internal procedural error,” and Mr. Draghi played down the sensitivity of the disclosure, saying that publicly available information on the ECB’s bond purchases already reflected the information Mr. Coeuré disclosed.

—Noemie Bisserbe and Todd Buell contributed to this article.