The number of mobile phones in circulation in Brazil rose 1.88% in May from April to 157.5 million as Mother's Day fueled sales in the period, according to figures released by telecommunications regulator Anatel late Thursday.

Net additions increased to 2.9 million in May, compared with 923,000 seen in April.

Vivo Participacoes (VIV) maintained leadership of the Brazilian mobile-phone market with a 29.38% share of subscriptions in May, down slightly from 29.5% seen in April. Vivo is jointly owned by Spain's Telefonica SA (TEF) and Portugal Telecom (PT).

Claro, the local unit of Mexico's America Movil SA (AMX), was second with a 25.51% share last month, down from 25.8% seen in the previous month.

In the meantime, TIM Participacoes (TSU) was in third place with 23.59% in May, stable from April. TIM is the local unit of Telecom Italia SpA (TI).

Fourth-placed mobile-phone operator Oi (TNE) saw its market share increase to 21.14% in May, from 20.7% seen in April. Oi launched cell-phone operations in Sao Paulo, Brazil's richest state, late last year.

-By Rogerio Jelmayer, Dow Jones Newswires; 55-11-2847-4521; rogerio.jelmayer@dowjones.com