Some investors anticipated that Facebook would be up today — but I don’t know anyone who envisioned a 12.5% pop to about $22.33 in mid-afternoon trading even as about 804M additional shares became available for sale. Indeed, the conventional wisdom held that history could repeat itself and the price could fall with the third expiration of a so-called lockup period which prevented many Facebook insiders from trading their shares immediately after the company went public in May. Today’s lockup expiration was the largest. Although the share price is still far below the IPO price of $38, it’s an improvement from early September when Facebook hit a low of $17.55. The company reassured investors last month that its ad sales can continue to grow even as Facebook users increasingly access the service from smartphones. “While the stock will likely require another quarter of outperformance vs. expectations to move much above current prices, we believe a support level is mostly in place, implying limited downside from here regardless of the manner in which the lock-up expiration plays out,” says Pivotal Research Group analyst Brian Wieser.