As part of its popular whistleblower program, the Securities and Exchange Commission promises to move swiftly on useful information about potential wrongdoing. But the agency isn’t as speedy when it comes to paying off its tipsters.

Of the 297 whistleblowers who have applied for awards since 2011, about 247-or roughly 83%-haven't received a decision from the SEC, according to data obtained by The Wall Street Journal in response to a public-records request. Some of the award claims have been delayed more than two years.