(Reuters) - Hedge fund manager Daniel Loeb on Thursday disclosed a $1 billion-plus stake in Japan's SoftBank Corp (>> Softbank Corp) at an investment conference, while another top money manager warned in an interview of the "bubble-like" conditions of some stocks.

Loeb was a speaker at the Robin Hood Investors Conference along with hedge fund manager David Einhorn of Greenlight Capital, who disclosed a stake in chipmaker Micron Technology (>> Micron Technology, Inc.), lifting its shares 6.3 percent. Einhorn also defended his stake in Apple Inc (>> Apple Inc.).

A spokeswoman for Third Point LLC confirmed via email that Loeb, its chief executive, said at the conference Third Point had a stake of "$1 billion plus" in SoftBank.

Einhorn mentioned holding several short positions and captured the mood of many when he warned that while it is hard to say if markets are in a bubble, certain stocks are behaving in a "bubble-like fashion" for reasons such as lacking profits. Einhorn did not name any specific companies.

Einhorn made the "bubble-like" comment in an interview on CNBC after speaking at the conference in New York, which was closed to the media.

Barry Sternlicht, chief executive officer of real-estate investor Starwood Capital Group and also a speaker at the conference, told CNBC he does not think there is a bubble in housing.

But he added that markets in some cities "got way ahead of themselves" as housing prices far outpaced job growth, such as in Las Vegas, Nevada, and Phoenix, Arizona.

The conference was sponsored by The Robin Hood Foundation, a New York City anti-poverty charity founded by Paul Tudor Jones of Tudor Investment Corp.

Its board members include Sternlicht, Einhorn and other well-known figures such as Laurence Fink, chief executive of asset manager BlackRock Inc (>> BlackRock, Inc.) and Jeffrey Immelt, chief executive of General Electric Co (>> General Electric Company).

SOFTBANK AS ALIBABA PROXY

SoftBank and U.S. search firm Yahoo Inc (>> Yahoo! Inc.) both own large stakes in Alibaba Group Holding, China's largest e-commerce company. It is poised for an initial public offering that could value the firm at more than $100 billion, in turn driving up shares of its investors ahead of the offering.

For his part, Einhorn said he has taken a stake in Micron because the chipmaker stands to benefit from industry consolidation and defended his investment in Apple, citing the company's software sales and technology, like the fingerprint-reader in its new iPhone.

However, Einhorn said he remains short on Green Mountain Coffee Roasters Inc (>> Green Mountain Coffee Roasters Inc.), citing rising competition from other makers of coffee-brewing packets, and short also on Chipotle Mexican Grill Inc (>> Chipotle Mexican Grill, Inc.), which he said will have trouble raising prices to become more profitable.

(Reporting by Ross Kerber; additional reporting by Tim McLaughlin; Editing by Gerald E. McCormick, Bernard Orr and Kenneth Barry)

By Ross Kerber and Tim McLaughlin