Albertsons is once again preparing to go public, said people familiar with the matter, as the company's backers look to tap into a strong stock market to cash out of an investment that dates back nearly 15 years. The company, which also owns the Safeway and Jewel-Osco chains, expects to decide in coming weeks whether to proceed with an initial public offering that could value it around $19 billion, one of the people said. Albertsons has been updating initial public offering documents that have been filed confidentially with the Securities and Exchange Commission, the people said.