LeBron James Miami Heat video pushes prediction markets toward Miami

A deleted LeBron James Miami Heat video has shifted prediction markets toward Miami as traders try to read the next stop in James’ free agency. The Miami Heat accidentally posted and then removed a YouTube video titled “LeBron James Introductory Press Conference” on Tuesday night, according to the Miami Herald.

A team spokesperson told the Miami Herald the upload was an error and said the club had prepared materials in case James decided to join the Heat this offseason. Fortune reported that, after the video came down, the team reposted a LinkedIn listing for a Director of YouTube Strategy.

James has been a free agent since leaving the Los Angeles Lakers 24 days ago, according to Fortune. His agent, Rich Paul, said this week that no one, including Paul or NBA commissioner Adam Silver, knows when James will make his decision, Fortune reported.

Will LeBron James join the Miami Heat?

Prediction markets moved sharply after the deleted post. Polymarket priced Miami near 50% to land James, while Kalshi had the same outcome in the high 40s, according to Fortune.

Polymarket data cited by Fortune showed Miami at 31.5% on the night of the mistaken post, behind Cleveland by three percentage points. That means the Heat’s market-implied chances rose by about 20 points after the video appeared and disappeared.

Prediction markets let users trade contracts tied to future events, with prices often read as implied odds. In this case, traders are buying and selling contracts tied to which NBA team James will join next.

How much money is in the LeBron James market?

Trading tied to James’ next team has exceeded $245 million across Kalshi and Polymarket, Yahoo Sports reported. Kalshi alone shows more than $211 million in volume on its James landing-spot market, according to the platform.

That is a rapid increase from earlier figures. Fortune reported that the market stood at $76 million just weeks ago, and Kalshi later said volume had passed $170 million; the current Kalshi total indicates an increase of more than $40 million in three days after that report.

At one point, the James contract ranked as Kalshi’s third-largest market ever, behind only the 2026 World Cup champion market and the 2028 Democratic presidential nomination market, according to Fortune. Fewer than 30 Kalshi markets have crossed $100 million in volume, Fortune reported.

By comparison, Kalshi markets tied to the free agencies of Kawhi Leonard, Bronny James, Kyle Tucker and Jaelan Phillips each drew well under $1 million combined, according to Fortune.

Why the Heat post matters to regulators and leagues

Marty Conway, a sports business professor at Georgetown University, told Fortune the episode reflects a broader pattern in sports and politics, where people believe they can gain an edge before news becomes public. He said he could not determine whether the Heat video was posted intentionally and said there was no evidence either way.

Conway told Fortune that the existence of prepared materials still suggests the Heat saw James as a possible target. He also said mistakes can happen when unfinished materials sit on internal systems before publication.

The NBA has told federal regulators it opposes markets like the James contract, Fortune reported. The league has argued that such markets can encourage front-office leaks, while Kalshi is fighting state regulators over whether its sports contracts are financial products or unlicensed sports betting, according to Fortune.

Pew Research Center found that monthly volume on Kalshi and Polymarket reached nearly $24 billion as of April, with sports traders more active than those betting on politics or crypto, according to Fortune. The James episode shows how quickly even a deleted team post can become a market-moving event when traders are looking for signs in free agency.

This story draws on original reporting from Fortune.