NEW YORK — The big pop in Facebook Inc. shares never came.

Facebook stock closes at $38.23, a gain of 23 cents, on its first day as a public company.

Buyers did not rush into the market to snap up shares of the social networker. And the big Wall Street banks that brought Facebook public scrambled to prevent the stock from collapsing into declines.

The underwriters averted a potential debacle by scooping up shares of the company during the Nasdaq debut. This propped up the stock, keeping it above the $38 offering price through most of the day.

“When a deal gets priced and breaks price on the first day, that’s definitely a major embarrassment,” said trader Andrew Frankel, co-president of Stuart Frankel & Co. “But it didn’t do that here _ at least for the time being.”

The practice is pretty standard during IPOs, especially high-profile ones like Facebook. The big banks buy into a wave of selling as a way to prevent their customers from suffering big losses.

The syndicate of underwriters led by Morgan Stanley helped prop up shares after the Nasdaq Stock Market experienced technical problems processing trades. A number of brokerages reportedly said they were having problems trying to trade the stock.

“There are currently industrywide delays in reporting trade executions,” Michael Cianfrocca, a spokesman for brokerage Charles Schwab, told Bloomberg News. “These issues do not appear to be unique to Schwab.”

The problems could threaten the Nasdaq’s reputation as the premier platform to list big blue-chip technology companies. The exchange won a hard-fought battle against the New York Stock Exchange for a chance to list Facebook.

Spokesmen for the Nasdaq did not return several telephone calls and emails seeking comment.

Many traders, Frankel said, “backed away from trading Facebook because Nasdaq had such system issues.”

The stock bolted at the open to $42.05, but then quickly withered in the first hour of trading. It touched $38 several times.

Barry Ritholtz, head of Fusion IQ, an investment research firm, added: “It pretty much started straight down to $38, where as normally happens, the underwriters defended it.”