Is DeepSeek V4 cheaper than Gemini 3.5 Flash for SEC extraction?

Yes, substantially: V4.1-Flash is $0.30/$1.20 per million input/output at peak against Gemini 3.5 Flash's $1.50/$9, 5x cheaper on input and 7.5x on output, and twice that gap off-peak. For output-heavy structured extraction across thousands of filings that gap dominates the bill. The Gemini premium buys ecosystem maturity, not lower token cost, so cost-sensitive batch work favors DeepSeek (DeepSeek verified 2026-10-02).

Does DeepSeek V4 fit a full 10-K in context?

Yes. Both V4 variants carry a 1M-token window with up to 384K tokens of output per request, comfortably holding a full 10-K without chunking, which removes a class of overlap and stitching bugs. Gemini 3.5 Flash also offers a large window per Google's docs. For long single-document extraction both avoid forced chunking; the differentiator is per-token price.

What is the catch with DeepSeek pricing?

It depends on the hour. DeepSeek bills peak rates from 01:00 to 04:00 and 06:00 to 10:00 UTC on weekdays and half that at every other time, so V4.1-Flash is $0.30/$1.20 at peak and $0.15/$0.60 off-peak, and V4-Pro $1.32/$3.96 at peak. Schedule large extraction runs off-peak and budget at the peak rate for anything that cannot wait.

DeepSeek V4 vs Gemini 3.5 Flash: SEC Extraction 2026

Education, not investment advice. Past performance does not predict future results. How we check our numbers.

The short answer

For SEC filing extraction in 2026, DeepSeek V4.1-Flash is much cheaper at $0.30/$1.20 per million input/output tokens at peak (half off-peak) with a 1M-token context window, versus Gemini 3.5 Flash at $1.50/$9: 5x on input and 7.5x on output. On raw extraction cost DeepSeek wins clearly; pay the Gemini premium for ecosystem, reliability, and integration.

For SEC filing extraction at scale in 2026, DeepSeek V4 vs Gemini 3.5 Flash is a price-versus-ecosystem call. DeepSeek V4.1-Flash is much cheaper: $0.30 per million input and $1.20 per million output tokens at peak, half that off-peak, with a 1M-token context window that swallows a full 10-K. Gemini 3.5 Flash costs $1.50 per million input and $9 per million output, 5x DeepSeek's peak rate on input and 7.5x on output (10x and 15x against off-peak), but brings Google's tooling, reliability and broad integration. On raw extraction cost DeepSeek wins clearly; pay the Gemini premium for ecosystem and operational maturity. Price your own filing volume in the Token-Cost Optimizer.

TL;DR

Model	Input ($/1M)	Output ($/1M)	Context window
DeepSeek V4.1-Flash	$0.30	$1.20	1M tokens
DeepSeek V4-Pro	$1.32	$3.96	1M tokens
Gemini 3.5 Flash	$1.50	$9.00	large (Google docs)

DeepSeek prices are peak rates; off-peak (outside 01:00-04:00 and 06:00-10:00 UTC on weekdays) they halve. DeepSeek verified against its official pricing page on 2026-10-02, Gemini on 2026-05-26.

Why this pairing matters for filings

SEC filing extraction is a long-context, high-volume, structured-output job: feed a 10-K or 10-Q, pull out specific line items, sections, or facts, and do it across thousands of filings. Two costs dominate — the input tokens of long documents and the output tokens of structured results — so per-token price and context window decide the bill. Both contenders are built for exactly this: DeepSeek's 1M-token window holds an entire filing without chunking, and Gemini 3.5 Flash is Google's frontier-intelligence-at-Flash-speed tier aimed at agentic workloads.

DeepSeek V4: the cost leader

DeepSeek V4.1-Flash (API model name deepseek-flash) lists at $0.30 per million input tokens and $1.20 per million output tokens at peak, with a 1M-token context window and up to 384K tokens of output per request. V4-Pro, the reasoning-heavier variant, lists at $1.32 input and $3.96 output at peak. Every DeepSeek rate halves off-peak, and cache-hit input costs a fiftieth of a cache miss ($0.006 against $0.30 on Flash), which matters when you reuse a long system prompt across many filings.

For pure extraction throughput, this is the cheapest credible option here by a wide margin. The 1M context means a full 10-K rarely needs chunking, removing a class of overlap and stitching bugs. The tradeoffs are ecosystem and operational: fewer native integrations than Google's stack, and time-of-day pricing, so schedule batch runs off-peak and budget at the peak rate for anything that cannot wait. DeepSeek has repriced twice in 2026; re-check the rate before a large run.

Gemini 3.5 Flash: the ecosystem premium

Gemini 3.5 Flash lists at $1.50 per million input tokens and $9 per million output tokens — frontier-tier intelligence at Flash speed, but not budget pricing. That is 5x DeepSeek V4.1-Flash's peak rate on input and 7.5x on output. The output multiple is the one that bites on extraction, because structured pulls can be output-heavy.

What the premium buys is the Google ecosystem: mature SDKs, reliability, broad platform integration, and a model family you can scale up or down within. For a production pipeline where operational maturity and vendor stability outweigh raw token cost, that premium is often defensible. For a cost-sensitive batch job over thousands of filings, it is hard to justify against DeepSeek.

The decision

Minimize cost per filing, comfortable operating a leaner ecosystem: DeepSeek V4.1-Flash, run off-peak.
Need a reasoning-heavier extractor, still cost-conscious: DeepSeek V4-Pro ($1.32 / $3.96 at peak).
Production pipeline where ecosystem, reliability, and integration outweigh token cost: Gemini 3.5 Flash.
Output-heavy structured extraction: the output-price gap ($1.20 vs $9.00 at peak) favors DeepSeek sharply.

A common pattern is to extract with DeepSeek V4 for cost, then spot-check a sample with a higher-tier model to validate field accuracy before trusting the pipeline at scale.

Validate accuracy, not just price

Cheapest tokens do not mean correct extractions. Numeric precision and field grounding fail silently on filings, so a cost win means nothing if the numbers are wrong. Run a labeled sample through whichever model you pick and check field-level accuracy; the Token-Cost Optimizer prices your exact filing volume and prompt shape so the cost comparison reflects your workload, not a headline rate.

Gemini 3.5 Flash vs GPT-5.5 vs Opus 4.8 Finance Extraction 2026: the three-way frontier comparison.
Cheapest LLM for SEC 10-K Extraction Across 10,000 Filings 2026: the cost model at batch scale.
Best LLM APIs for SEC Filing Extraction 2026: the full model field for filings work.

Connects to

Token-Cost Optimizer: price your filing volume across models.
Hallucination Detector: catch ungrounded numbers in extracted fields.
SEC Filing Chunk Optimizer: chunking strategy when context limits bite.

Sources

DeepSeek API Models & Pricing, api-docs.deepseek.com/quick_start/pricing (accessed 2026-10-02).
Google AI for Developers, Gemini 3.5 Flash pricing (accessed 2026-05-26).

Frequently asked questions

Is DeepSeek V4 cheaper than Gemini 3.5 Flash for SEC extraction?: Yes, substantially: V4.1-Flash is $0.30/$1.20 per million input/output at peak against Gemini 3.5 Flash's $1.50/$9, 5x cheaper on input and 7.5x on output, and twice that gap off-peak. For output-heavy structured extraction across thousands of filings that gap dominates the bill. The Gemini premium buys ecosystem maturity, not lower token cost, so cost-sensitive batch work favors DeepSeek (DeepSeek verified 2026-10-02).
Does DeepSeek V4 fit a full 10-K in context?: Yes. Both V4 variants carry a 1M-token window with up to 384K tokens of output per request, comfortably holding a full 10-K without chunking, which removes a class of overlap and stitching bugs. Gemini 3.5 Flash also offers a large window per Google's docs. For long single-document extraction both avoid forced chunking; the differentiator is per-token price.
What is the catch with DeepSeek pricing?: It depends on the hour. DeepSeek bills peak rates from 01:00 to 04:00 and 06:00 to 10:00 UTC on weekdays and half that at every other time, so V4.1-Flash is $0.30/$1.20 at peak and $0.15/$0.60 off-peak, and V4-Pro $1.32/$3.96 at peak. Schedule large extraction runs off-peak and budget at the peak rate for anything that cannot wait.