Alibaba shares surged 5% on Hong Kong's stock exchange on
the news.
His absence had fuelled speculation over his whereabouts
amid increasing official scrutiny of his businesses.
Tianmu News, a news portal under Zhejiang Online, a
government-backed news website, reported on Wednesday, that Mr Ma addressed the
teachers as part of one of his charity foundation's initiatives.
The annual event is usually hosted in the resort city of
Sanya, but was held online this year because of Covid-19 restrictions.
"We cannot meet in Sanya due to the epidemic," he
said in the speech.
"When the epidemic is over, we must find time to make
up for everyone's trip to Sanya, and then we will meet again!"
In the video, he was dressed in a blue pullover and spoke
directly to the camera from a room with grey marble walls and a striped carpet.
It was not clear from the video or the Tianmu News article
where he was speaking from.
Regulatory scrutiny
Last month, China's central bank hauled in executives from
Ant Group and ordered a major shake-up of the company's operations.
Mr Ma is a founder and key shareholder of Ant Group, which
is China's biggest payments provider.
Before ordering the shakeup of the company, regulators had
already scuppered Ant Group's listing on the Hong Kong and Shanghai exchanges.
The $37bn share market offering was expected to be the
biggest of 2020.
Separately, China's State Administration for Market
Regulation announced an investigation into Alibaba over monopolistic practices.
Suspicions about Mr Ma's whereabouts were raised earlier
this month, when he missed the recording of Africa's Business Heroes, a
television show on which he was a judge.
Although Alibaba attributed his absence to a scheduling
conflict, several media reports said he had not been seen since making comments
that were seen as critical of China's banking system at a public event in
Shanghai in October.