(Reuters) -Berkshire Hathaway sold about one-third of its stake in VeriSign, an internet infrastructure and domain name registry company that Warren Buffett's conglomerate has invested in since 2012, VeriSign said on Monday.

The sale of 4.3 million VeriSign shares at $285 each generated gross proceeds of about $1.23 billion, reducing Berkshire's ownership stake to 9.6% from 14.2%.

Buffett's company may sell an additional 515,032 shares to meet demand, and VeriSign will receive no proceeds from the sale, VeriSign said.

VeriSign, based in Reston, Virginia, said the sale was intended to reduce Berkshire's stake to below 10%, a threshold that triggers regulatory obligations.

The price was a 6.9% discount to VeriSign's closing price of $305.98. In after-hours trading, VeriSign shares fell 5.9% to $288.00. Berkshire did not immediately respond to a request for comment outside business hours.

Buffett's company owned about 13.29 million VeriSign shares as of March 31, a regulatory filing shows.

That stake was worth about $4.07 billion before the sale, based on the $305.98 closing price. VeriSign traded at less than one-sixth that level when Berkshire began buying.

Berkshire ended March with $347.7 billion of cash, and through that month was a net seller of stocks for 10 straight quarters.

It had nevertheless been adding to its VeriSign stake as recently as January.

Berkshire's smaller investments in technology-related companies have often been spearheaded by Buffett's portfolio managers, Todd Combs and Ted Weschler.

Buffett, 94, has run Omaha, Nebraska-based Berkshire since 1965. He is expected to step down as chief executive at the end of the year and be replaced by Vice Chairman Greg Abel, 63. Buffett would remain chairman.

JPMorgan Securities underwrote the VeriSign share sale.