Sirius XM Radio, the largest US satellite-radio broadcaster, rose the most in more than a month in New York trading, on speculation John Malone’s Liberty Media will increase its stake and spin it off.

Sirius rose 4.5 percent to $2.31 at the close, the largest one-day gain since Feb. 24.

Liberty, based in Englewood, Colo., owns preferred stock convertible into about 40 percent of the common shares of New York-based Sirius. Speculation about a stake increase intensified after Liberty asked US regulators this month for permission to gain majority control of Sirius, said Brett Harriss, a Gabelli analyst in Rye, NY. He has a “hold” rating on Sirius.

“There’s speculation they will increase their stake to go from 40 percent to 51 percent and then divest the stake,” Harriss said.