arbiter
JournalsAccount

Social media, high‐frequency trading, and market making after‐hours – Evidence from presidential tweets

Stefan Scharnowski

Journal of Financial Research2026https://doi.org/10.1111/jfir.70049article
AJG 3ABDC A
Weight
0.50

Abstract

I analyze differences between the core and extended trading sessions in the high‐frequency reaction of equity markets to potential news. Using presidential tweets as unanticipated, potentially market‐stirring events, I find that volatility increases and liquidity deteriorates within fractions of a second after a tweet. The speed of quote adjustments indicates that algorithmic traders monitor social media sources around the clock and automatically trade upon this information. Compared to the core trading session, the reduction in market quality is much stronger and faster during the extended trading hours, when liquidity is lower and designated market maker participation is optional.

Open via your library →

Cite this paper

https://doi.org/https://doi.org/10.1111/jfir.70049

Or copy a formatted citation

@article{stefan2026,
  title        = {{Social media, high‐frequency trading, and market making after‐hours – Evidence from presidential tweets}},
  author       = {Stefan Scharnowski},
  journal      = {Journal of Financial Research},
  year         = {2026},
  doi          = {https://doi.org/https://doi.org/10.1111/jfir.70049},
}

Paste directly into BibTeX, Zotero, or your reference manager.

Flag this paper

Social media, high‐frequency trading, and market making after‐hours – Evidence from presidential tweets

Flags are reviewed by the Arbiter methodology team within 5 business days.

Evidence weight

0.50

Balanced mode · F 0.40 / M 0.15 / V 0.05 / R 0.40

F · citation impact0.50 × 0.4 = 0.20
M · momentum0.50 × 0.15 = 0.07
V · venue signal0.50 × 0.05 = 0.03
R · text relevance †0.50 × 0.4 = 0.20

† Text relevance is estimated at 0.50 on the detail page — for your query’s actual relevance score, open this paper from a search result.