B737 captain reported a near midair collision with a light twin during climb.

Attributes
ACN	1727150
Time
Date	202002
Local Time Of Day	0001-0600
Place
Locale Reference	A90.TRACON
State Reference	NH
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Climb
Flight Plan	IFR
Aircraft 2
Make Model Name	Small Aircraft Low Wing 2 Eng Retractable Gear
Person 1
Function	Pilot Flying Captain
Qualification	Flight Crew Instrument Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	ATC Issue All Types Conflict NMAC Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance

Narrative:

Had an RA and turned and descended 400 ft. To avoided traffic. Controller sent us on a heading and altitude to fly close to a light twin. [We] banked hard to the left and lost 400 ft.

Original NASA ASRS Text

Title: B737 Captain reported a NMAC with a light twin during climb.

Narrative: Had an RA and turned and descended 400 ft. to avoided traffic. Controller sent us on a heading and altitude to fly close to a light twin. [We] banked hard to the left and lost 400 ft.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.