* Q3 oper EPS $0.74 vs est $0.74

* Net premiums earned rises 150 pct

* Sees Q4 oper EPS $0.86-$0.96

* Sees FY10 oper EPS $3.50-$3.70

Nov 5 (Reuters) - Property and casualty insurer Tower Group Inc (TWGP.O: Quote, Profile, Research) posted a 63 percent rise in quarterly operating profit as net premiums earned rose due to acquisitions.

Tower Group said it also achieved "meaningful organic growth" through continued expansion of its specialty business and brokerage business outside the Northeast.

For the third quarter, the company posted an operating income of $30.2 million, or 74 cents a share, compared with $18.5 million, or 79 cents a share, last year.

Analysts on average had expected a profit of 74 cents a share, before items, according to Thomson Reuters I/B/E/S.

Revenue nearly doubled to $256.3 million from last year.