** Shares of asset management firm TPG TPG.O rise 3.3% to $69.9

** Homebuilder Lennar's LEN.N shares fall 1.7% to about $103.8 in morning trading

** TPG acquires majority interest in Lennar's multifamily development and investment management platform

** TPG commits an additional $1 billion for LEN's business, the companies say

** "This partnership reflects our shared commitment to tackling one of America's most pressing challenges: housing affordability," LEN's CEO Stuart Miller says

** As of last close, TPG stock up 2.9% and LEN stock down 19.3% over the past year

(Reporting by Megavarshini G. Somasundaram in Bengaluru)

((Megavarshini.SomasundaramGnanasundari@thomsonreuters.com))