Key Highlights

  • Centrus Energy was trading 0.45% lower at $108.93 on October 28, 2026, a day after an 11.15% rise.
  • NANO Nuclear Energy was trading 2.27% lower at $12.06, the steepest decline of the five names.
  • Short interest runs from 27.9% of shares outstanding at Array Technologies to 37.68% of float at Eos Energy Enterprises, on different bases.
  • FuelCell Energy holds $737.3 million of cash and restricted cash against $33.0 million of quarterly revenue.
  • Eos Energy Enterprises and Array Technologies both report third-quarter results on November 5, 2026.

Which Nuclear, Fuel-Cell and Storage Stocks Are Trading Lower on October 28?

Five energy names were trading lower on Wednesday, October 28, 2026, and each carries a large short position. Centrus Energy (NYSEAMERICAN:LEU) was trading 0.45% lower at $108.93 after an 11.15% rise on Tuesday. NANO Nuclear Energy (NASDAQ:NNE) was trading 2.27% lower at $12.06, FuelCell Energy (NASDAQ:FCEL) 1.72% lower at $11.97, Eos Energy Enterprises (NASDAQ:EOSE) 0.82% lower at $1.80 and Array Technologies (NASDAQ:ARRY) 1.03% lower at $3.36.

No company release dated today explains any of the five moves. Four are tied directly to nuclear fuel, reactors, fuel cells or batteries, while Array makes solar trackers and fits the group only loosely, as energy infrastructure. The sections below condense each stock's report.

Centrus Energy: Why Is the Stock Little Changed After an 11.15% Rise?

Centrus shares gained 11.15% on Tuesday, October 27, to $109.42, and were trading 0.45% lower at $108.93 on Wednesday. No company release dated October 27 or 28 explains either move. The company supplies enriched uranium fuel and is expanding enrichment capacity, including high-assay low-enriched uranium (HALEU).

Short interest for the October 15 settlement date was 5,933,422 shares, about 29.7% of shares outstanding (calculated, not a float measure), with 6.79 days to cover. Centrus agreed on October 19 to buy Westerman Holdings for about $116 million. Second-quarter revenue was $176.1 million, 2026 guidance of $450 million to $500 million was maintained, and offtake agreements include one with Oklo (NYSE:OKLO).

NANO Nuclear Energy: What Does 31.2% Short Interest Mean for a $12 Stock?

NANO Nuclear shares were trading 2.27% lower at $12.06, and no dated company release accompanied the move. At 53.70 million shares the market value is roughly $647.6 million (calculated). The company is developing small modular reactors, including the KRONOS MMR, the ZEUS portable battery reactor and the LOKI MMR for space use.

Short interest for the September 30 settlement date was 16,750,169 shares, about 31.2% of shares outstanding (calculated, as float is not reported), with 7.95 days to cover. Cash and short-term investments were about $580 million at June 30, 2026. The Nuclear Regulatory Commission docketed the KRONOS permit application in May 2026, with construction expected in the second half of 2027.

FuelCell Energy: Why Is a Heavily Shorted Stock Slipping 1.72%?

FuelCell Energy shares were trading 1.72% lower at $11.97, and no release dated today explains the dip. Short interest for the September 30 settlement date was 24,465,442 shares, or 32.37% of float, with about 4.6 days to cover. About 79.95 million shares put the market value near $957 million (calculated).

The company builds stationary fuel cell power platforms and has pivoted toward data center power. Fiscal third-quarter revenue to July 31 was $33.0 million versus $46.7 million a year earlier, and the net loss narrowed to $45.3 million. Committed backlog was $1.296 billion, and deliveries under the first 30 megawatt phase of a data center agreement are expected to begin in the fiscal fourth quarter.

Eos Energy Enterprises: Why Is the Battery Maker Slipping Despite a Record Quarter?

Eos shares were trading 0.82% lower at $1.80 in a session without a new company release. The Pittsburgh company makes zinc-based battery energy storage systems. Preliminary third-quarter revenue of $82 million to $83 million was a record, up about 169% to 172% from a year earlier, though the figures remain subject to closing procedures.

GAAP gross margin was still negative, at negative 55% to negative 53%. Short interest for the September 30 settlement date was 134,847,658 shares, or 37.68% of float, with 4.7 days to cover. Backlog was about $765 million and cash, including restricted cash, about $344 million. The full report is due before the market opens on November 5.

Array Technologies: How Large Is the Short Position Before the November 5 Report?

Array shares were trading 1.03% lower at $3.36, and no company release dated October 28 accompanied the move. The company supplies solar trackers, fixed-tilt systems and foundations. Short interest for the October 15 settlement date was 42,984,386 shares, up about 12.9% (calculated) from the prior settlement, with 6.61 days to cover.

That equals about 27.9% of the 154.01 million shares outstanding, a share of outstanding stock rather than of float. Second-quarter revenue was $342.1 million versus $362.2 million, and the orderbook reached a record $2.5 billion, up 37%. Third-quarter revenue guidance is $310 million to $330 million, with results due after the close on November 5.

Nuclear, Fuel-Cell and Storage Stocks Compared: Moves, Short Interest and Size

NANO Nuclear had the largest decline at 2.27% and Centrus the smallest at 0.45%, a gap of 1.82 percentage points (calculated). FuelCell Energy, Array and Eos fell 1.72%, 1.03% and 0.82%. At $108.93, Centrus trades at about 9.0 times NANO Nuclear's $12.06 share price (calculated), and its market value of about $2.17 billion is roughly 4.2 times Array's near $517 million (calculated).

Short interest cannot be ranked on one scale. On shares outstanding, NANO Nuclear's 31.2% (September 30) is 3.3 percentage points above Array's 27.9% (October 15), with Centrus at 29.7% (calculated). On float, Eos at 37.68% is 5.31 percentage points above FuelCell Energy at 32.37% (calculated). By days to cover, NANO Nuclear's 7.95 is 3.35 days above FuelCell Energy's 4.6 (calculated). Settlement dates also differ, and float and shares-outstanding percentages are not directly comparable.

What to Watch Next: November 5 Reports and the Next Short-Interest Figures

November 5, 2026 is the busiest date: Eos reports before the market opens, Array reports after the close, and Centrus holds its shareholder call at 8:30 a.m. ET. The October 30 short-interest settlement for Centrus and Array is expected to be published on November 10. FuelCell Energy awaits Phase 0 deliveries and results for the fiscal fourth quarter ending October 31, while NANO Nuclear's fiscal year-end report to September 30 has no stated date.