Comcast will pay $110,000 to be a top-level “presenting sponsor” at the Walter Kaitz Foundation’s annual dinner in September, at which Clyburn is receiving the “diversity advocate” award, according to a foundation spokeswoman. Time Warner Cable paid $22,000 in May to the foundation for the same event, according to a Senate lobbying disclosure filed at the end of last month. The foundation supports diversity in the cable industry.

There are no rules preventing businesses from helping to honor regulators in this way, and both companies say they have supported the foundation for years.

But one watchdog is pointing out the appearance of a conflict.

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“I think that the timing is curious,” said Carrie Levine, research director at Citizens for Responsibility and Ethics in Washington, which noted the corporate sponsorships in a blog post Monday. “They’re honoring an FCC commissioner at the exact same time they’re trying to get approval for a merger. And that doesn’t look so good.”

The contributions come as FCC and Justice Department officials review the $45 billion megadeal, which would give Comcast control of about 30 percent of U.S. pay-TV subscribers and about 40 percent of the country’s broadband market. The two firms are pitching the deal as a way to increase investment in cable and Internet technology, but public interest groups oppose the deal because they say the combined company will have too much control over the market.

Clyburn, a Democrat and former acting chairwoman of the FCC, is known as a major advocate for media industry diversity. Her office declined to comment on the Comcast and Time Warner Cable sponsorships of the foundation dinner.

Time Warner Cable’s contribution to the dinner is dated May 14, according to the company’s disclosure. The Comcast-Time Warner Cable merger was announced in February.

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Comcast spokeswoman Sena Fitzmaurice said the company has supported the foundation for decades and said Clyburn’s role as an awardee has no bearing on its sponsorship.

“We absolutely dispute the notion that our contributions have anything to do with currying favor with Commissioner Clyburn or any honoree,” she said in a statement. “Such claims are insulting and not supported by any evidence. They are purely fiction. We have supported the organization year in and year out regardless of who the dinner honorees have been.”

Comcast has given similar amounts to the foundation’s annual dinner in recent years, according to figures provided by the company.

A Time Warner Cable spokesman also said the company has consistently donated to the foundation and said the firm was not concerned about the appearance of sponsoring a dinner honoring one of the regulators who oversees it.

“The [foundation] is the centerpiece of this industry’s efforts to not just recruit but to advance and train people of multi-ethnicity,” said spokesman Bobby Amirshahi. “The reality is the honoree was not a consideration for us as one of many companies that supported [the dinner.]”

This year, however, is the first time that a sitting FCC commissioner has been honored, according to the list of past award recipients on the foundation’s website. The foundation was launched in 1981.

The honorees are chosen by the foundation’s dinner committee, foundation spokeswoman Joy Sims said. That panel includes Comcast CEO Brian Roberts, as well as several other telecom executives. Companies including Cox Communications, Univision and Time Warner (which is separate from Time Warner Cable) are also sponsoring the dinner this year.

Comcast and Time Warner Cable, like the rest of the telecom industry, have robust lobbying operations in Washington and are working hard to win approval for their proposed merger.

Comcast itself, as well as media firms like Discovery and ESPN, have been honored at the dinner in the past. Tom Wheeler, the current chairman of the FCC, was honored at the inaugural dinner in 1984, though at the time he was chairman of the National Cable and Telecommunications Association and did not serve in government.