CUPERTINO, Calif. — A dubious proposition from the outset, a rumored fall iPad update is looking increasingly unlikely, AllThingsDigital reported Monday.

There may well be an iPad 3 in the pipeline, but it will likely not be seen until next year, said J.P. Morgan analyst Mark Moskowitz.

“In recent months, there has been rising investor speculation that a new iPad 3 would be launched for the holiday season,” Moskowitz wrote in a research note to clients. “Our latest research continues to indicate that there is no such device slated for production this year. … There are prototypes in the supply chain related to the next-generation device, but our conversations with industry participants suggest that a new device will not be available until sometime in calendar 2012.”

The iPad 2 launched in March and holds a 68.3 percent share of the tablet market, according to the latest metrics from the market research firm International Data Corporation.

With that massive a share and no true rival to threaten it, there’s little reason to expedite the next version of the device, Moskowitz said.

“We do not think Apple needs to be in a rush to unveil a new iPad,” he wrote. “The other tablet entrants have stumbled so far, and that trend-line could persist deep into 2012. Motorola Mobility and Research In Motion have been recent disappointments, and we expect more stumbles from others.”