Navient Corp. /zigman2/quotes/204528402/composite NAVI +0.80% shares rose more than 6% in the extended session Tuesday after the company reported better-than-expected earnings. The financial services company reported fourth-quarter net income of $171 million, or 78 cents a share, compared with $72 million, or 63 cents a share, in the year-ago period. Navient reported adjusted diluted core earnings of 67 cents a share versus 58 cents a share a year ago. Analysts surveyed by FactSet had estimated adjusted earnings of 58 cents a share, and for the first quarter model adjusted earnings of 70 cents a share. Navient stock has gained 27% over the past year, with the S&P 500 index /zigman2/quotes/210599714/realtime SPX -0.38% rising 25%.