UPDATE 1-Lexinfintech slashes U.S. IPO size as China reins in micro-lenders

* Lexinfintech had filed in Nov to raise up to $500 mln

* Selling 12 mln ADS at between $9 and $11 each - new filing

* Beijing targeted online micro-lenders with new rules this month (Adds company response, background on firm and industry)

HONG KONG, Dec 14 (Reuters) - Chinese consumer lending firm Lexinfintech has slashed the size of its U.S. initial public offering by two-thirds to a maximum possible $151.8 million, following a recent crackdown by Beijing on fast-growing online micro-lenders.

Lexinfintech, which focuses on loans to educated young adults between 18 and 36, including loans for online shopping, had planned to raise up to $500 million in an IPO on the Nasdaq, according to a filing it made to the U.S. Securities and Exchange Commission in November.

China's financial regulators are attempting to curb unwieldy growth at the nation's online micro-lenders, unveiling tougher new rules earlier this month including a ban on loans to borrowers who have no source of income.

In a U.S. securities filing on Wednesday, Lexinfintech said it would sell 12 million American Depositary Shares at a price of between $9 and $11 each. The price range suggests an issue size of between $108 million and $132 million.

It said it could realize up to $151.8 million from the offering upon exercise of overallotment options and $122.3 million after deducting expenses.

When asked about the lower IPO size, Lexinfintech said in an email the $500 million figure provided at the time of the November filing was for the purpose of determining the registration fee and that the number of shares being offered and the price range had not been estimated then.

Lexinfintech had an outstanding principal balance of $2.39 billion on its books as on September 30, 2017. On-balance sheet loans amounted to $1.67 billion and assets totaled $1.89 billion which were partially funded by short term debt of $1.51 billion.

The company has about 3.3 million customers with an average customer loan balance of $887.

Micro-lending is booming in China as lenders seek to cash in on rising incomes in a country where credit card penetration remains at about one-third of the population, according to central bank data.

China's online cash loan sector is projected to reach 2.9 trillion yuan by 2020, according to Oliver Wyman.

But authorities have launched a crackdown amid criticism that users of small, unsecured "cash loans," which can be issued by mobile phone apps, are vulnerable to exaggerated advertising and aggressive debt collection. (Reporting by Umesh Desai; Editing by Edwina Gibbs and Muralikumar Anantharaman)