NEW YORK » Nielsen is buying Arbitron for about $1.26 billion.

The radio audience ratings company will give Nielsen a clearer picture of unmeasured areas of media consumption like streaming audio.

Nielsen Holdings N.V. provides global data about what people watch and buy. The company said today that it will pay $48 per share, which is a 26 percent premium to Arbitron’s Monday closing price of $38.04.

Arbitron Inc., based in Columbia, Md., currently has about 26.2 million outstanding shares, according to FactSet.

The acquisition is expected to add about 13 cents per share to Nielsen’s adjusted earnings a year after closing and about 19 cents per share to adjusted earnings two years after closing.

The boards of both companies have approved the deal.

Nielsen has headquarters in the Netherlands and New York.