Linkup Research releases open-source sparse embedding model SPARSEUP with 149 million parameters
Linkup Research has released SPARSEUP, an open-source sparse embedding model built on a 149 million-parameter ModernBERT backbone and distributed under the Apache 2.0 license. According to the team, the model posted an average nDCG@10 score of 56.4 on the BEIR-13 benchmark. It also described SPARSEUP as the strongest known sparse encoder under 150 million parameters that uses a public vocabulary. The model weights are hosted on Hugging Face and can be loaded through either Transformers or Sentence Transformers. Linkup Research said the release is meant to fill the sparse retrieval gap left after LightOn recently introduced DenseOn and LateOn, while keeping the same backbone family and fine-tuning data so the three retrieval styles can be compared side by side. On MS MARCO, SPARSEUP averages 47 non-zero terms per query and 190 per document. Using the Seismic inverted index, it reaches more than 97% recall in about 380 microseconds per query on a single thread.








