The Challenge: Manual Forecast Consolidation

Every forecasting cycle, finance teams chase down spreadsheets from regions, business units, and cost centers. Each file has its own layout, naming logic, and hidden assumptions. Consolidation means copying, pasting, fixing broken links, and reconciling versions just to get to a single view of the numbers. By the time the consolidated forecast is ready, many of the underlying assumptions are already outdated.

Traditional approaches – shared network drives, email submissions, and even sophisticated linked workbooks – no longer scale. The more your organisation grows, the more fragile these setups become. A single overwritten cell, a changed tab name, or a missing file can break the entire consolidation chain. Finance ends up maintaining a complex spreadsheet ecosystem instead of running a robust, driver-based financial planning process.

The impact is substantial. Manual consolidation introduces avoidable errors, slows down planning cycles, and limits how many scenarios you can realistically run. Business stakeholders wait days or weeks for updated views, making it harder to react to market shifts, supply disruptions, or demand spikes. Instead of enabling proactive, dynamic planning, your forecasting process becomes a bottleneck and a source of tension between finance and the rest of the business.

The good news: this is a solvable problem. Modern AI tools like Gemini integrated with Google Sheets and BigQuery can standardise templates, automate consolidation logic, and even generate predictive scenarios once the data is clean. At Reruption, we’ve repeatedly replaced brittle spreadsheet workflows with AI-supported processes that finance teams can actually trust and own. In the rest of this page, you’ll find practical, concrete guidance on how to move from manual consolidation to an automated, AI-ready forecasting setup.

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Our Assessment

A strategic assessment of the challenge and high-level tips how to tackle it.

From Reruption’s work building real-world AI automations in finance-like workflows, we’ve seen the same pattern: the hardest part of fixing manual forecast consolidation is not the math, it’s the process. Gemini for forecast consolidation works best when it sits on top of a clear data model and well-defined ownership. Used correctly with Google Sheets and BigQuery, Gemini can become the engine that unifies templates, cleans data, and produces consolidated views in minutes instead of days.

Define a Single Source of Truth Before You Automate

Before asking Gemini to consolidate anything, you need to decide what “truth” looks like in your planning process. That means clearly defining your chart of accounts, cost center hierarchy, entity structure, and key drivers. If each region uses its own naming or time granularity, Gemini will still be guessing. Automation amplifies whatever structure you give it – good or bad.

Strategically, treat BigQuery as your central planning data store and Google Sheets as the front-end for submission and review. This separation lets finance teams keep their familiar spreadsheet interface while Gemini works against a stable, governed model in the background. Investing time upfront in that model pays off every forecast cycle that follows.

Position Gemini as a Co-Pilot, Not a Black Box

For finance leaders, control and auditability are non-negotiable. If AI-based forecast consolidation feels like a black box, adoption will stall. Frame Gemini as a co-pilot that executes your consolidation rules, highlights anomalies, and suggests scenarios – but leaves final decisions with finance.

Design your setup so that every automated consolidation step is explainable: which sources were used, which mappings applied, what exceptions were flagged. This builds trust and makes it easier for controllers and FP&A to challenge and refine the logic over time, instead of bypassing it and falling back to manual work.

Start with a Narrow Forecasting Scope and Expand

Trying to automate the entire enterprise forecasting process in one go is risky. A better strategic approach is to pick one cycle or scope – for example, OPEX forecasting for one region or selected cost centers – and implement Gemini-driven consolidation end-to-end there.

This gives you a realistic sandbox to test template standards, data flows into BigQuery, and Gemini’s role in cleaning, mapping, and summarising submissions. Once the approach proves itself in one slice of the business, you can scale to more regions, P&Ls, and planning horizons with much less resistance.

Clarify Roles Between Finance, IT, and Data Teams

Automating manual forecast consolidation with Gemini is not just a tooling decision; it’s an operating model change. Decide early who owns templates, who manages the BigQuery data model, who configures Gemini, and who approves changes to business rules. Without clear ownership, you’ll drift back into spreadsheet chaos.

A pragmatic model is: finance owns drivers, assumptions, and review workflows; data/BI owns the core data model in BigQuery; and an AI engineering partner like Reruption takes responsibility for the Gemini prompts, automations, and integration glue. This division keeps finance in control of planning while ensuring the technical backbone remains robust.

Design for Auditability and Risk Management from Day One

Regulators, auditors, and boards increasingly expect transparency in how forecasts are produced. When you introduce AI into financial planning, you must show where AI is used, how results are validated, and how overrides are handled. Build Gemini into your process with explicit checkpoints rather than letting it silently change numbers.

That means keeping version histories, logging AI-generated transformations, and requiring human approvals for material changes. Strategically, this does two things: it keeps risk within acceptable boundaries, and it gives you an auditable story about how automated consolidation has improved control and reduced manual error – which is often stronger than the status quo.

Used thoughtfully, Gemini with Google Sheets and BigQuery turns forecast consolidation from a manual, error-prone exercise into a controlled, repeatable process that can scale with your business. The key is combining a solid data foundation with clear roles and explainable AI logic so finance gains speed without giving up control. Reruption’s engineers and Co-Preneur teams specialise in building exactly these kinds of AI-first workflows inside organisations; if you want to explore what automated forecast consolidation could look like in your environment, we’re ready to help you test it quickly and safely.

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Real-World Case Studies

From Energy to Fintech: Learn how companies successfully use Gemini.

BP

Energy

BP, a global energy leader in oil, gas, and renewables, grappled with high energy costs during peak periods across its extensive assets. Volatile grid demands and price spikes during high-consumption times strained operations, exacerbating inefficiencies in energy production and consumption. Integrating intermittent renewable sources added forecasting challenges, while traditional management failed to dynamically respond to real-time market signals, leading to substantial financial losses and grid instability risks . Compounding this, BP's diverse portfolio—from offshore platforms to data-heavy exploration—faced data silos and legacy systems ill-equipped for predictive analytics. Peak energy expenses not only eroded margins but hindered the transition to sustainable operations amid rising regulatory pressures for emissions reduction. The company needed a solution to shift loads intelligently and monetize flexibility in energy markets .

Lösung

To tackle these issues, BP acquired Open Energi in 2021, gaining access to its flagship Plato AI platform, which employs machine learning for predictive analytics and real-time optimization. Plato analyzes vast datasets from assets, weather, and grid signals to forecast peaks and automate demand response, shifting non-critical loads to off-peak times while participating in frequency response services . Integrated into BP's operations, the AI enables dynamic containment and flexibility markets, optimizing consumption without disrupting production. Combined with BP's internal AI for exploration and simulation, it provides end-to-end visibility, reducing reliance on fossil fuels during peaks and enhancing renewable integration . This acquisition marked a strategic pivot, blending Open Energi's demand-side expertise with BP's supply-side scale.

Ergebnisse

  • $10 million in annual energy savings
  • 80+ MW of energy assets under flexible management
  • Strongest oil exploration performance in years via AI
  • Material boost in electricity demand optimization
  • Reduced peak grid costs through dynamic response
  • Enhanced asset efficiency across oil, gas, renewables
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Nubank (Pix Payments)

Payments

Nubank, Latin America's largest digital bank serving over 114 million customers across Brazil, Mexico, and Colombia, faced the challenge of scaling its Pix instant payment system amid explosive growth. Traditional Pix transactions required users to navigate the app manually, leading to friction, especially for quick, on-the-go payments. This app navigation bottleneck increased processing time and limited accessibility for users preferring conversational interfaces like WhatsApp, where 80% of Brazilians communicate daily. Additionally, enabling secure, accurate interpretation of diverse inputs—voice commands, natural language text, and images (e.g., handwritten notes or receipts)—posed significant hurdles. Nubank needed to overcome accuracy issues in multimodal understanding, ensure compliance with Brazil's Central Bank regulations, and maintain trust in a high-stakes financial environment while handling millions of daily transactions.

Lösung

Nubank deployed a multimodal generative AI solution powered by OpenAI models, allowing customers to initiate Pix payments through voice messages, text instructions, or image uploads directly in the app or WhatsApp. The AI processes speech-to-text, natural language processing for intent extraction, and optical character recognition (OCR) for images, converting them into executable Pix transfers. Integrated seamlessly with Nubank's backend, the system verifies user identity, extracts key details like amount and recipient, and executes transactions in seconds, bypassing traditional app screens. This AI-first approach enhances convenience, speed, and safety, scaling operations without proportional human intervention.

Ergebnisse

  • 60% reduction in transaction processing time
  • Tested with 2 million users by end of 2024
  • Serves 114 million customers across 3 countries
  • Testing initiated August 2024
  • Processes voice, text, and image inputs for Pix
  • Enabled instant payments via WhatsApp integration
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Duolingo

EdTech

Duolingo, a leader in gamified language learning, faced key limitations in providing real-world conversational practice and in-depth feedback. While its bite-sized lessons built vocabulary and basics effectively, users craved immersive dialogues simulating everyday scenarios, which static exercises couldn't deliver . This gap hindered progression to fluency, as learners lacked opportunities for free-form speaking and nuanced grammar explanations without expensive human tutors. Additionally, content creation was a bottleneck. Human experts manually crafted lessons, slowing the rollout of new courses and languages amid rapid user growth. Scaling personalized experiences across 40+ languages demanded innovation to maintain engagement without proportional resource increases . These challenges risked user churn and limited monetization in a competitive EdTech market.

Lösung

Duolingo launched Duolingo Max in March 2023, a premium subscription powered by GPT-4, introducing Roleplay for dynamic conversations and Explain My Answer for contextual feedback . Roleplay simulates real-life interactions like ordering coffee or planning vacations with AI characters, adapting in real-time to user inputs. Explain My Answer provides detailed breakdowns of correct/incorrect responses, enhancing comprehension. Complementing this, Duolingo's Birdbrain LLM (fine-tuned on proprietary data) automates lesson generation, allowing experts to create content 10x faster . This hybrid human-AI approach ensured quality while scaling rapidly, integrated seamlessly into the app for all skill levels .

Ergebnisse

  • DAU Growth: +59% YoY to 34.1M (Q2 2024)
  • DAU Growth: +54% YoY to 31.4M (Q1 2024)
  • Revenue Growth: +41% YoY to $178.3M (Q2 2024)
  • Adjusted EBITDA Margin: 27.0% (Q2 2024)
  • Lesson Creation Speed: 10x faster with AI
  • User Self-Efficacy: Significant increase post-AI use (2025 study)
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H&M

Apparel Retail

In the fast-paced world of apparel retail, H&M faced intense pressure from rapidly shifting consumer trends and volatile demand. Traditional forecasting methods struggled to keep up, leading to frequent stockouts during peak seasons and massive overstock of unsold items, which contributed to high waste levels and tied up capital. Reports indicate H&M's inventory inefficiencies cost millions annually, with overproduction exacerbating environmental concerns in an industry notorious for excess. Compounding this, global supply chain disruptions and competition from agile rivals like Zara amplified the need for precise trend forecasting. H&M's legacy systems relied on historical sales data alone, missing real-time signals from social media and search trends, resulting in misallocated inventory across 5,000+ stores worldwide and suboptimal sell-through rates.

Lösung

H&M deployed AI-driven predictive analytics to transform its approach, integrating machine learning models that analyze vast datasets from social media, fashion blogs, search engines, and internal sales. These models predict emerging trends weeks in advance and optimize inventory allocation dynamically. The solution involved partnering with data platforms to scrape and process unstructured data, feeding it into custom ML algorithms for demand forecasting. This enabled automated restocking decisions, reducing human bias and accelerating response times from months to days.

Ergebnisse

  • 30% increase in profits from optimized inventory
  • 25% reduction in waste and overstock
  • 20% improvement in forecasting accuracy
  • 15-20% higher sell-through rates
  • 14% reduction in stockouts
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Mastercard

Payments

In the high-stakes world of digital payments, card-testing attacks emerged as a critical threat to Mastercard's ecosystem. Fraudsters deploy automated bots to probe stolen card details through micro-transactions across thousands of merchants, validating credentials for larger fraud schemes. Traditional rule-based and machine learning systems often detected these only after initial tests succeeded, allowing billions in annual losses and disrupting legitimate commerce. The subtlety of these attacks—low-value, high-volume probes mimicking normal behavior—overwhelmed legacy models, exacerbated by fraudsters' use of AI to evade patterns. As transaction volumes exploded post-pandemic, Mastercard faced mounting pressure to shift from reactive to proactive fraud prevention. False positives from overzealous alerts led to declined legitimate transactions, eroding customer trust, while sophisticated attacks like card-testing evaded detection in real-time. The company needed a solution to identify compromised cards preemptively, analyzing vast networks of interconnected transactions without compromising speed or accuracy.

Lösung

Mastercard's Decision Intelligence (DI) platform integrated generative AI with graph-based machine learning to revolutionize fraud detection. Generative AI simulates fraud scenarios and generates synthetic transaction data, accelerating model training and anomaly detection by mimicking rare attack patterns that real data lacks. Graph technology maps entities like cards, merchants, IPs, and devices as interconnected nodes, revealing hidden fraud rings and propagation paths in transaction graphs. This hybrid approach processes signals at unprecedented scale, using gen AI to prioritize high-risk patterns and graphs to contextualize relationships. Implemented via Mastercard's AI Garage, it enables real-time scoring of card compromise risk, alerting issuers before fraud escalates. The system combats card-testing by flagging anomalous testing clusters early. Deployment involved iterative testing with financial institutions, leveraging Mastercard's global network for robust validation while ensuring explainability to build issuer confidence.

Ergebnisse

  • 2x faster detection of potentially compromised cards
  • Up to 300% boost in fraud detection effectiveness
  • Doubled rate of proactive compromised card notifications
  • Significant reduction in fraudulent transactions post-detection
  • Minimized false declines on legitimate transactions
  • Real-time processing of billions of transactions
Read case study →

Best Practices

Successful implementations follow proven patterns. Have a look at our tactical advice to get started.

Standardise Forecast Templates in Google Sheets

Start by enforcing a single, standardised forecast template across all regions and business units in Google Sheets. Lock structural elements like time periods, account codes, and cost center fields, and make variable inputs (volumes, prices, drivers) clearly identifiable. This consistency is what allows Gemini to process and consolidate submissions reliably.

Use data validation and dropdowns for entities, cost centers, and account codes to reduce free-text input and mapping errors. Store the master template in a controlled folder and use Apps Script or Workspace add-ons to distribute copies to contributors with controlled sharing permissions.

Load Submissions into BigQuery as a Staging Layer

Don’t let consolidation live only in spreadsheets. Configure an automated pipeline (using Apps Script, Dataform, or similar) that writes each submitted Google Sheet into a BigQuery staging table. Include metadata like region, business unit, version, and submission timestamp so you can filter and audit later.

From there, define transformation queries that unify currencies, time granularity, and account mappings into a standard planning schema. This is the dataset Gemini will read, clean, and summarise – giving you a single, reliable layer for analytics and reporting beyond the spreadsheets.

Use Gemini to Clean, Map, and Flag Anomalies

Once your forecast submissions land in BigQuery, use Gemini to automate data cleaning and anomaly detection. For example, you can have Gemini review new forecast lines against historical actuals and prior forecasts, then flag unusual variances or missing entries for finance review.

In a Gemini-connected environment, prompts might look like this:

Role: You are a financial planning assistant helping with forecast consolidation.

Task: Analyze the latest forecast data (current_forecast) against:
- Last forecast (previous_forecast)
- Last 4 quarters of actuals (actuals_4q)

For each cost center and account combination:
- Flag any variance > 20% vs previous_forecast
- Flag any variance > 30% vs average of actuals_4q
- Suggest likely reasons based on seasonality and driver changes
- Propose a cleaned version where obvious data entry mistakes exist

Output a JSON payload with:
- cost_center
- account
- original_forecast
- suggested_correction
- variance_flags
- explanation

Embed this into a scheduled process so controllers receive a pre-analysed list of issues each cycle rather than hunting manually through thousands of lines.

Automate Consolidated Views and Management Summaries

After cleaning and validation, use Gemini to generate consolidated forecast views and narrative summaries that finance can directly review with management. Have Gemini pull from the curated BigQuery tables and produce P&L, cost center, and region-level aggregates, then generate commentary on main drivers and changes.

Example prompt for a management summary:

Role: You are an FP&A analyst summarizing the new consolidated forecast.

Input data:
- consolidated_forecast table (current cycle)
- previous_forecast table (last cycle)
- variance_analysis table (by region and account)

Task:
- Summarize total revenue, gross margin, and EBIT vs last forecast
- Highlight top 5 positive and top 5 negative variances with concrete drivers
- Identify 2-3 risks and 2-3 opportunities based on the forecast
- Keep language concise and suitable for an executive audience

Output: 5-8 bullet points followed by a short narrative (max 400 words).

This turns raw consolidated numbers into “finance-ready” output in minutes, while leaving review and approval firmly with your FP&A team.

Enable What-If Scenarios Directly from the Consolidated Data

One of the biggest advantages of having consolidation automated and centralised is that you can finally explore dynamic, driver-based scenarios without rebuilding everything manually. Use Gemini to apply parameter changes (e.g. volume growth, FX rates, price changes) to your BigQuery-based forecast and generate alternative views.

Here’s an example prompt pattern:

Role: You are a scenario planning assistant for the finance team.

Input:
- consolidated_forecast_base
- scenario_parameters: { volume_delta_pct_by_region, fx_rates, price_change_pct_by_product_line }

Task:
- Apply the scenario_parameters to the base forecast
- Recalculate revenue, gross margin, and EBIT by region and business unit
- Compare scenario results vs base forecast
- Output tables plus a short explanation of the key changes.

Connect these scenarios back to Google Sheets dashboards or Looker Studio to let finance and business leaders interact with the results without touching the underlying logic.

Track KPIs for Process Quality and Speed Improvements

To prove the value of Gemini-based forecast consolidation, define and monitor a small set of KPIs. Examples include: time from submission deadline to consolidated view, number of manual adjustments after AI cleaning, number of detected anomalies per cycle, and the share of templates submitted correctly on first attempt.

Visualise these in a simple dashboard so you can show stakeholders how automation has reduced cycle times and error rates over successive planning rounds. This also helps you prioritise where to refine templates, rules, or prompts next.

When implemented in this way, organisations typically see consolidation time cut from days to hours, a measurable reduction in manual errors, and a higher share of time spent on analysis and scenarios instead of mechanical data work. The goal is not to remove finance judgment, but to free it from low-value tasks so planning can become faster, more dynamic, and more strategically relevant.

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Frequently Asked Questions

Gemini reduces manual consolidation by standardising inputs, automating data cleaning, and generating consolidated views from a central dataset. Instead of copying and pasting across dozens of spreadsheets, forecast submissions flow from Google Sheets into BigQuery, where Gemini applies mapping rules, checks for anomalies, and produces unified forecast tables.

Finance then works with a single, trusted source of forecast data, plus AI-generated variance reports and summaries. The result is fewer manual touchpoints, fewer formula errors, and significantly faster closing of each forecasting cycle.

You typically need three capabilities: finance process expertise, basic data engineering, and AI configuration skills. Finance defines the planning model, drivers, and approval workflows. A data/BI profile sets up BigQuery tables, data flows from Google Sheets, and access controls. An AI engineer or technically inclined analyst works on Gemini prompts and automations, integrating them into your existing tooling.

Reruption often covers the AI engineering and integration side, working directly with your finance and BI teams. This reduces the need to hire a dedicated AI team just to get started and helps you transfer knowledge so the setup can be owned internally over time.

For a focused scope (for example, OPEX forecasting for one region or business unit), you can usually see tangible results within one or two planning cycles. A first Gemini-powered consolidation pilot can often be stood up in a few weeks: standardise the template, connect Google Sheets to BigQuery, configure basic prompts for cleaning and anomaly detection, and generate a consolidated view.

From there, each subsequent cycle becomes faster and more automated as you refine mapping rules, expand coverage to more entities, and add scenario capabilities. Full enterprise-wide automation is an iterative journey, but the benefits begin as soon as one part of your forecasting process is transitioned to the new model.

The main cost components are engineering time to set up the data pipelines and Gemini workflows, plus ongoing AI usage fees. Compared to the cumulative hours senior finance staff spend on manual consolidation each year, payback is often quick. Typical ROI comes from reduced cycle time, lower error rates, and the ability to run more and better scenarios without extra effort.

Instead of just looking at tool cost, consider the value of having consolidated forecasts ready days earlier, with higher quality. This supports faster decision-making in areas like hiring, inventory, and investments. Many organisations find that the saved time of controllers and FP&A alone justifies the investment, even before accounting for better decisions enabled by more dynamic planning.

Reruption specialises in building AI-first finance workflows that actually run inside your organisation, not just on slide decks. With our 9.900€ AI PoC offering, we can quickly test whether Gemini can automate a meaningful slice of your forecast consolidation – from defining the use case and data requirements to delivering a working prototype and performance metrics.

Beyond the PoC, our Co-Preneur approach means we embed with your team, help design the data model in BigQuery, standardise Google Sheets templates, configure Gemini prompts, and set up governance and security. We take entrepreneurial ownership of outcomes alongside you and leave you with a production-ready setup and a clear roadmap for scaling AI across your financial planning processes.

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