China's state-backed Tsinghua Unigroup Ltd is preparing a $23 billion bid for U.S. memory chip maker Micron Technology Inc (MU.O), in what would be the biggest Chinese takeover of a U.S. company, people familiar with the matter said.

The technology conglomerate is prepared to bid $21 per share for Micron, a 19.3 percent premium to the stock's close on Monday. The offer could come as early as Wednesday, a person close to Tsinghua told Reuters, although a Micron spokesman said it had not received an offer.

A successful bid to acquire Micron would consolidate Unigroup's position as a champion for China's technological development, after it struck deals and research partnerships with international firms in the semiconductor industry.