Jack Dorsey, CEO and co-founder of Twitter, announced Tuesday that bidding on the first tweet ever sent will end on March 21, and that he will accept the winning bid, donating the proceeds to charity.

On Friday night, Dorsey flagged the listing for the genesis tweet on Valuables, a program for selling tweets authenticated by their authors, created by the startup Cent.

Bidding on the tweet has sat at $2.5 million since March 6. The bid is from Sina Estavi, the CEO of Tron's oracle network, Bridge. The prior high bid was $2 million from Tron founder Justin Sun.

GiveDirectly is a non-profit organization that specializes in giving direct cash transfers to low-income people, without strings attached. "Africa response" in Dorsey's tweet likely refers to its "COVID-19 Africa Response" campaign. That program is just under $5 million short of its goal. Even if sold at the current bid it would almost be enough to close that gap.

GiveDirectly was early to accepting donations in cryptocurrency. "We've accepted crypto for a while, and think there's some philosophical similarity (e.g., focus on efficiency of payments, especially through tech, individual empowerment, etc.) which has persuaded a number of folks to give directly," Michael Faye, the organization's president, told CoinDesk in a February email.

The pace of crypto donations has accelerated. As of mid-February, GiveDirectly had received more than $20 million worth of crypto donations, with $5 million from the Pineapple Fund in 2017, more than $5 million across two separate gifts from Ethereum founder Vitalik Buterin and $10 million from an anonymous donor. 

It's not clear why Dorsey is converting the funds to BTC before donating (the sale will close in ether), though the Twitter CEO is keen on supporting BTC development in Africa. The GiveDirectly FAQ says it can accept donations in a variety of cryptocurrencies.

A spokesperson for Twitter declined to provide further comment. GiveDirectly was not immediately available for a comment on Dorsey's pledge.