One major fund is betting that Signet’s margin rebound is just getting started.On November 14, New York City-based Summit Street Capital Management disclosed a new position in Signet Jewelers (SIG +0.31%), acquiring 264,054 shares valued at $25.3 million, according to its latest SEC filing.What HappenedAccording to a November 14 SEC filing, Summit Street Capital Management reported a new stake in Signet Jewelers of 264,054 shares, valued at $25.3 million as of September 30. This position accounts for 3.5% o ...