E*Trade sells wealth unit to Massachusetts rival

* E*Trade sells adviser unit to local rival

* Combined firm to have $2.3 bln in assets

BOSTON, March 21 (Reuters) - Adviser Investments, the wealth manager begun by well-known Vanguard Group analyst Dan Wiener, is buying a rival in the Boston suburbs, Kobren Insight Management, from E*Trade Financial Corp, the companies said on Monday.

Terms were not disclosed.

Adviser Investments of Newton, Massachusetts, has about $1.3 billion under management and is known for its financial newsletters including one tracking fund giant Vanguard written by Adviser Investments Chairman Wiener. Another newsletter follows Fidelity Investments and is written by Jim Lowell, Adviser Investment's chief investment officer.

The deal will give the combined firm another $1 billion that Kobren, of Wellesley, Massachusetts, previously had under management, said Dan Silver, Adviser Investments president.

Kobren Chief Investment Officer Rusty Vanneman will join the new firm as Chief Investment Strategist, Silver said. Kobren Fixed Income Strategist Chris Keith also will join the new firm, which will keep the Adviser Investments name.

Both firms were started in the 1980s. The founder of the smaller one, Eric Kobren, had sold the business to E*Trade in late 2005 and retired. Silver said the combined firm will have about 45 professionals, including 20 from the former Kobren business, and that no layoffs are expected. (Reporting by Ross Kerber; Editing by Phil Berlowitz)