Casual games developer Zynga (News - Alert) Inc. is said to be preparing a secondary share offering, following its initial public offering (IPO) in December.

According to a report byBloomberg, Zynga isn’t issuing new stock in the planned offering and will not receive any proceeds. The move is happening rather as a way of allowing investors to gain liquidity on the stock, while convincing those with larger holdings to commit to a longer “lockup” period that discourages them from selling shares.

Insiders within companies are usually banned from unloading shares for a six-month period following an IPO. This measure is party enforced in order to prevent sell orders from flooding the stock market and disrupting the share price too much.

By pursuing a secondary offering, Zynga hopes to avoid the fate that befell the professional social network, LinkedIn (News - Alert) Corp, whose owner saw its stock fall after its lockup period ended in November.

Zynga’s new offering will be held before its lockup ends in June, according to Bloomberg’s (News - Alert) unnamed sources.

Carter Mack, president of investment bank JMP Group Inc. said that in a secondary offering, venture capital investors and other short-term investors usually sell some of their stock to long-term shareholders like investment banks under the proviso that they agree to a longer lockup period.

Zynga sold about 14 percent of its shares in its IPO, though other Web-based companies (including LinkedIn, Groupon Inc, and Pandora (News - Alert) Media Inc.) have offered less than 10 percent of shares in their respective IPOs. They do so in order to protect the value of previous investors’ stock by not flooding the market with shares.

The games company makes most of its revenue through Facebook (News - Alert).com, which it usesasaplatform for its games. Facebook Inc., meanwhile, has filedtoholditsownIPO.