Vacancy increased in the 159,982-unit Suburban Maryland apartment market, just breaking the 4.0% mark. The rate was 4.1% for the fourth quarter of 2015, up 30 basis points from the prior quarter and up 10 from one year earlier. The rate was unchanged in January. The average asking rent and the average effective rent increased 0.7% in the fourth quarter to $1,464 and $1,415 per month. These rates were up 2.8% and 2.7% over 12 months. January data show 0.1% gains for asking and effective rents.